The Logon User Interface DLL Ctxgina.dll failed to load. Contact your system administrator to replace the DLL, or restore the original DLL

Symptoms

When rebooting a MetaFrame Presentation (XenApp) Server, you receive the following error message:

"User Interface Failure. The Logon User Interface DLL Ctxgina.dll failed to load."

Causes

Potential causes of this error message include:
Corrupted or deleted *GINA.DLL,
Failed installation (or uninstallation) of Metaframe Presentation (XenApp) Server or its corresponding service packs, hotfix rollup packs, or hotfixes.
An install conflict with applications such as the Novell Client, PCAnywhere, or any key that modifies the HKLM\Software\Microsoft\WindowsNT\Current Version\Winlogon\GinaDLL value.
Incomplete or missing Path statements set in Environment Variables.