Some ".tar.gz" compressed files contain malware. Therefore, some malware detectors warn about every ".tar.gz" compressed file, whether it contains good software or malware or no software at all, on the "better safe than sorry" principle.
My brief inspection of this file persuades me that it is what it claims to be, source code to a WikiEngine. It looks like innocent PHP source code to me. Any competent PHP programmer can quickly confirm or deny that claim. (-: I hope you are not too insulted by my implication that you are not a "competent PHP programmer" :-). --DavidCary 20:06, 18 July 2009 (EDT)