diff --git a/src/structure/components/com_sportsmanager/views/sportsmanager/view_admin.php b/src/structure/components/com_sportsmanager/views/sportsmanager/view_admin.php
index 134719a..4b669dc 100644
--- a/src/structure/components/com_sportsmanager/views/sportsmanager/view_admin.php
+++ b/src/structure/components/com_sportsmanager/views/sportsmanager/view_admin.php
@@ -6,7 +6,7 @@
 // kein direkter Zugriff
 defined('_JEXEC') or die('Restricted access');
 
-require_once(JPATH_COMPONENT . DIRECTORY_SEPARATOR . 'views/sportsmanager/view_tools.php');
+require_once(JPATH_ROOT . DIRECTORY_SEPARATOR . 'components' . DIRECTORY_SEPARATOR . 'com_sportsmanager' . DIRECTORY_SEPARATOR . 'views/sportsmanager/view_tools.php');
 
 class HTML_sportsmanager_admin
 {
@@ -1186,7 +1186,7 @@ class HTML_sportsmanager_admin
 		}
 	}
 
-	static function adminEditSpieler($row, $naechste_spielernr, $filter, $vereine, $vereinsmitgliedschaften, $beschraenkter_zugriff, $ansprechpartner_spielerdaten)
+    static function adminEditSpieler($row, $naechste_spielernr, $filter, $vereine, $vereinsmitgliedschaften, $beschraenkter_zugriff, $ansprechpartner_spielerdaten)
 	{
 		global $params;
 		?>
@@ -1194,7 +1194,7 @@ class HTML_sportsmanager_admin
             : <?php echo($row != null ? JText::_('COM_SPORTSMANAGER_CHANGING') : JText::_('COM_SPORTSMANAGER_ADD')); ?></div>
 
         <form action="<?php echo SportsManagerURL($row != null ? ('#id' . $row->spieler_id) : ''); ?>" method="post"
-              name="adminForm" id="adminForm" enctype="multipart/form-data">
+              name="adminForm" id="adminForm" enctype="multipart/form-data" onsubmit="return validate()">
             <div class="uk-overflow-auto"><table class="uk-table" width="100%">
                 <tr>
                     <td nowrap width="60%" valign="top">
@@ -1277,15 +1277,15 @@ class HTML_sportsmanager_admin
                                 </td>
                             </tr>
                             <tr>
-                                <td nowrap width="20%" align="right">
-									<?php echo JText::_('COM_SPORTSMANAGER_BIRTHDATE') ?>:
+                                <td nowrap width="20%" align="right" id="birthDateLabel">
+									<?php echo JText::_('COM_SPORTSMANAGER_BIRTHDATE') . '*' ?>:
                                 </td>
                                 <td nowrap>
 									<?php
 									if (!$beschraenkter_zugriff)
 									{
 										?>
-                                        <select class="uk-select uk-form-width-medium" name="datum_tag" size="1">
+                                        <select id="birthDay" class="uk-select uk-form-width-medium" name="datum_tag" size="1">
 											<?php
 											$datum = "0000-00-00";
 											if ($row != null)
@@ -1303,7 +1303,7 @@ class HTML_sportsmanager_admin
 											}
 											?>
                                         </select>
-                                        <select class="uk-select uk-form-width-medium" name="datum_monat" size="1">
+                                        <select id="birthMonth" class="uk-select uk-form-width-medium" name="datum_monat" size="1">
 											<?php
 											$datum_monat = substr($datum, 5, 2);
 											echo "<option value=\"0\"></option>";
@@ -1314,7 +1314,7 @@ class HTML_sportsmanager_admin
 											}
 											?>
                                         </select>
-                                        <select class="uk-select uk-form-width-medium" name="datum_jahr" size="1">
+                                        <select id="birthYear" class="uk-select uk-form-width-medium" name="datum_jahr" size="1">
 											<?php
 											$datum_jahr = substr($datum, 0, 4);
 											echo "<option value=\"0\"></option>";
@@ -1324,6 +1324,7 @@ class HTML_sportsmanager_admin
 											}
 											?>
                                         </select>
+                                        <small id="birthDateError" style="color: red"></small>
 										<?php
 									}
 									else if ($row != null && $row->geburtsdatum != null)
@@ -1623,6 +1624,27 @@ class HTML_sportsmanager_admin
             <input type="hidden" name="id" value="<?php echo($row != null ? $row->spieler_id : "0"); ?>"/>
             <input type="hidden" name="vereinsauswahl_anzahl" value="<?php echo $vereinsauswahl_anzahl; ?>"/>
         </form>
+        <script>
+            function validate() {
+                let isValid = true;
+
+                // Clear errors
+                document.getElementById("birthDateError").textContent = "";
+                document.getElementById("birthDateLabel").style.color = "";
+
+                const birthDay = document.getElementById("birthDay").value;
+                const birthMonth = document.getElementById("birthMonth").value;
+                const birthYear = document.getElementById("birthYear").value;
+
+                if(birthDay === '0' || birthMonth === '0' || birthYear === '0') {
+                    document.getElementById("birthDateError").textContent = "<?php echo JText::_('COM_SPORTSMANAGER_ERROR_BIRTHDAY_REQUIRED'); ?>";
+                    document.getElementById("birthDateLabel").style.color = "red";
+                    isValid = false;
+                }
+
+                return isValid;
+            }
+        </script>
 		<?php
 	}
 
diff --git a/src/structure/language/de-DE/de-DE.com_sportsmanager.ini b/src/structure/language/de-DE/de-DE.com_sportsmanager.ini
index eed0a37..d12ba2d 100644
--- a/src/structure/language/de-DE/de-DE.com_sportsmanager.ini
+++ b/src/structure/language/de-DE/de-DE.com_sportsmanager.ini
@@ -925,3 +925,5 @@ COM_SPORTSMANAGER_RANK="Rang"
 
 ; SPIELER BEARBEITEN
 COM_SPORTSMANAGER_LIZENZ="Lizenz"
+
+COM_SPORTSMANAGER_ERROR_BIRTHDAY_REQUIRED="Geburtstagsfelder dürfen nicht leer sein"
diff --git a/src/structure/language/en-GB/en-GB.com_sportsmanager.ini b/src/structure/language/en-GB/en-GB.com_sportsmanager.ini
index 8484415..5b8be65 100644
--- a/src/structure/language/en-GB/en-GB.com_sportsmanager.ini
+++ b/src/structure/language/en-GB/en-GB.com_sportsmanager.ini
@@ -921,3 +921,5 @@ COM_SPORTSMANAGER_NON_SMOKING_PROTECTION_MARK_NO=" (Kein Nichtraucherschutz)"
 COM_SPORTSMANAGER_POINTS_TABLE="Points table"
 COM_SPORTSMANAGER_EVALUATION="Auswertung"
 COM_SPORTSMANAGER_FUNCTION_DESCRIPTION="Variables: n = number of participants, p = place, m = multiplier of rating and in doubles possibly additionally reduced rating<br />Functions: +, -, *, /, round(x), pow(x), if(a > b, x, y), min(x, y), max(x, y), log(x), ln(x), logn(b, x)<br />VerteilungR(r, p, n, m) := max(round((((m * r - 1) * (-log(p / n) * (1 - (p / n)))) / (-log(1 / n) * (1 - (1 / n)))) + 1), 1)<br />Verteilung(r, p, n, m) := max(round(m * round((((r - 1) * (-log(p / n) * (1 - (p / n)))) / (-log(1 / n) * (1 - (1 / n)))) + 1)), 1)<br /><br />The functions VerteilungR() and Verteilung() distribute points for place 1 (r) descending to the individual places (p) of the number of participants (n).<br />VerteilungR() applies the multiplier (m) to the points for 1st place and then distributes down to 1 point for the last place.<br />Verteilung() applies the multiplier (m) to the points after the calculation, i.e. the last place receives 1 * m points."
+COM_SPORTSMANAGER_LIZENZ="License"
+COM_SPORTSMANAGER_ERROR_BIRTHDAY_REQUIRED="Birthday fields may not be empty"