500 Internal Server Error !

[eluser]MMCCQQ[/eluser]
hi

i got this error , i dont know why.. i dont have any .htaccess , inside or outside alpha subdomain..

http://alpha.tuenik.com/index.php/ <---500 Internal Server Error

http://alpha.tuenik.com/index.php/welcome <---- Work fine..

soo... what happed?

any help?