The maxfile size refers to the length of the filename in the file open dialog. The default for this is 256 characters. Is it possible that the length of the names of files you're trying to open (including the full path) is longer than 256 - not likely? If that's not it, do you have the latest version of the program? Also check the FAQ's on the website.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken