Warning(!)
My workarounds were just to point out to the problem. Not the complete just ctrl-c ctrl-v is the sollution... I said I didn't dig in too far..
preg_match and ereg are not the same and you should investigate what should be done to make the change of functions work correctly.
I noticed you changed some code where eregi also should work (case insensitive). Nice...
Now to be clear: The following is just one example... not all !!
Look at: fields/class.UploadField.php (#525)
This line gave a warning: if(preg_match('^image/', $sType) &&
Because simply change ereg for preg_match is not enough.