qmailadmin and vpopmail

[Essy Ren]

I've try install qmailadmin and there's a strange msg appear like this when i input the domain name and password that I've create with vpopmail what's my misconfiguration ? Internal Server Error The server encountered an internal error or misconfiguration and was unable to complete your request. Please contact the server administrator, [EMAIL PROTECTED] and inform them of the time the error occurred, and anything you might have done that may have caused the error. More information about this error may be available in the server error log. Apache/1.3.19 Server at riga.test.local Port 80