Contemplator is a wonderful site, and I use it without problems. Note that I don't rely on browser plugins to play Midi files - Iceweasel (Firefox clone) tells me I need to install a plugin to access all the site, but I ignore that.

I use a timidity to play Midi files on linux - it looks as though TiMidity (free from SoftPedia.com) is a similar program for Windows.

I've tried accessing contemplator using Firefox in WinXP (virtual) and get no warnings from Avast! antivirus. It may be that McAfee is overcautious, but I can't judge that.

Phil