Cannot Upload files on phpBB

I have a phpBB website on this server. Its whenever I upload anything, it says Server Parsing Error. Earlier it was uploading fine but now it doesn’t. phpBB guys say that the problem is in PHP.INI file that admin can access.
Please help me admin.They say that max file upload should be 25M and not 25MB. I am uploading only files that are less than 1 MB.

The upload limit is 8 MB, so uploading files less than 1 MB shouldn’t be any problem. What are you uploading?