I'm just about to release WP-Andreas01, a new theme based on one of my open source website templates. In this theme, I have included code from a plugin to add a nice extra feature (a dynamic sub-page menu). When I posted the first public version of the theme (it can be downloaded from: http://andreasviklund.com/blog/webdesign/the-download-link/), I got reports that it works perfectly for most people. But some of the users (from what I could tell, about 10-15%) are reporting an error that makes the theme impossible to load.
The error message (which appears at theme load) says: "Parse error: parse error, unexpected T_FUNCTION in /home/wp/public_html/wp-content/themes/wp-andreas01/functions.php on line 1"
functions.php contains the hacked plugin code, and since my PHP skills are very limited I wouldn't be surprised if I did something wrong. But noone has found any error in the file. It just doesn't work for some people. The problems seems to go away if all plugins are de-activated and then re-activated again. Error in the file transfers and a possible UTF-8 byte order mark error are two suggestions I have got, but if it was an BOM error the theme shouldn't work for anyone. Or am I wrong?
What could cause this? What does the message mean? Any feedback would be very welcome, as I will probably need to remove the functions.php if I can't find the error (if there is indeed any error).