[otrs] URGENT, got hacked! Where is index.pl?

I got hacked tonight and all my index.html and other index files are lost!! WHERE can I find the index.pl from OTRS? Is it saved somewhere else? In any directory? Or can I rebuild it? I have a very old version, 3.1.2 I think. Cannot check it right now, because I cannot access OTRS. Please help, this is urgent!! I need to have it back in order to work!! thanks, marc