SQL Error bei Installation

Fatal error: Could not execute prepared statement: SQLSTATE[42000]: Syntax error or access violation: 1068 Multiple primary key defined


id: ed136ea25f68e827c7be049a45d575ac986670e4
error message: Could not execute prepared statement: SQLSTATE[42000]: Syntax error or access violation: 1068 Multiple primary key defined
error code: 42000
sql type: wcf\system\database\MySQLDatabase
sql error: Multiple primary key defined
sql error number: 42000
sql version: 5.5.49-0+deb7u1
sql query: ALTER TABLE wcf1_contact CHANGE COLUMN contactID contactID int(10) NOT NULL AUTO_INCREMENT PRIMARY KEY
file: /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/system/database/statement/PreparedStatement.class.php (97)
php version: 5.5.35
wcf version: 2.1.10 (Typhoon)
date: Tue, 17 May 2016 15:46:42 +0000
request: /acp/index.php?install-package/&&
referer: https://www.borderline-forum.net/acp/index.php?package-installation-confirm/&queueID=1844&
Stacktrace:
#0 /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/system/database/editor/MySQLDatabaseEditor.class.php(126): wcf\system\database\statement\PreparedStatement->execute()
#1 /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/system/database/util/SQLParser.class.php(246): wcf\system\database\editor\MySQLDatabaseEditor->alterColumn('wcf1_contact', 'contactID', 'contactID', Array)
#2 /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/system/package/PackageInstallationSQLParser.class.php(316): wcf\system\database\util\SQLParser->executeAlterColumnStatement('wcf1_contact', 'contactID', 'contactID', Array)
#3 /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/system/database/util/SQLParser.class.php(159): wcf\system\package\PackageInstallationSQLParser->executeAlterColumnStatement('wcf1_contact', 'contactID', 'contactID', Array)
#4 /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/system/database/util/SQLParser.class.php(49): wcf\system\database\util\SQLParser->executeStatement('ALTER TABLE', 'ALTER TABLE wcf...')
#5 /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/system/package/plugin/SQLPackageInstallationPlugin.class.php(78): wcf\system\database\util\SQLParser->execute()
#6 /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/system/package/PackageInstallationDispatcher.class.php(571): wcf\system\package\plugin\SQLPackageInstallationPlugin->install()
#7 /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/system/package/PackageInstallationDispatcher.class.php(139): wcf\system\package\PackageInstallationDispatcher->executePIP(Array)
#8 /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/acp/action/InstallPackageAction.class.php(73): wcf\system\package\PackageInstallationDispatcher->install('84fb7269')
#9 /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/action/AbstractDialogAction.class.php(70): wcf\acp\action\InstallPackageAction->stepInstall()
#10 /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/action/AbstractAction.class.php(49): wcf\action\AbstractDialogAction->execute()
#11 /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/system/request/Request.class.php(58): wcf\action\AbstractAction->__run()
#12 /homepages/43/d599715531/htdocs/borderline-forum.net/wcf/lib/system/request/RequestHandler.class.php(139): wcf\system\request\Request->execute()
#13 /homepages/43/d599715531/htdocs/borderline-forum.net/acp/index.php(10): wcf\system\request\RequestHandler->handle('wbb', true)
#14 {main}