error when trying to upload files to b2evolution

[jazzencat]

I have installed b2evolution on my site. I can do posts and most other functions like creating new blogs and so forth. I cannot seem to upload files through b2evolution's upload function I just get this error: The file does not seem to be a valid upload! It may exceed the upload_max_filesize directive in php.ini. The files have been a 10kB txt file and a 33.1kB jpeg image. They are both _well_ below the 2MB limit. I cannot seem to find the relevant PHP file to change it. I have searched on Google, b2evolution's forums and other search engines. I have not found a newbie-friendly tutorial on how to correct this. (I don't understand scripter's jargon on the places that do tell what it is.) Can anyone help me out?