can't delete files in file manager

[za-zi.com]

I can't delete any files from my "file manager" under the httpdocs section
i keep selecting the files for deletion and the confirming, but they never get deleted!!

i just don't get it.

i loaded the site yesterday, everything was working.
today - i get a server error message.

everything was working like clock work yesterday and now everything is - not working - and of course..... no one is answering my tickets!!!!!

this is really turning out to be a bit of a nightmare...

some help please??????
i really am working against the clock...