It's what's called a "false positive". Anti-virus programs have a list of programs that're viruses, and looks for those file names, or files which are LIKE the ones on the list. Then there's"heuristics" where an AV program will look for virus-like activity. In this case, i think maybe there's a virus going around either called "ff7.exe", and/or it shares other similarities (like file size).
People on the GameFAQs forum also noted that ff7 and the High Res patch were giving off false positives. *shrugs*
funny, i use AVG and i haven't gotten any of this yet, either.