Problem with fopen(...) - "No error"??

I'm working against a table without problems, that is, as long as I insert and retrieve texts and numerical values from various fields. However, I'm also using a table for images, but I can't upload files correctly. This is the error I get : Warning: fopen("", "r") - No error in c:\code\wengine\aey.php on line 130 Warning: fread(): supplied argument is not a valid File-Handle resource in c:\code\wengine\aey.php on line 131 I have no clue what's the problem. I checked register_globals (on) but then again, that shouldn't matter 'cause I'm using the $_FILES variable to access the file information. Obviously, PHP thinks otherwise. It seems (from the warning "fopen("", "r")" above), that even so, $_FILES[userfile][tmp_name] is not recognized and just interpretated as null. I've tried $_FILES[userfile][name] also, but the same error occurs. The second error is obviously just an effect from the first, so what am I doing wrong here?? Any tips appreciated! Thanks, Arty