does not play well with others

For some odd reason, TiVo Desktop 2.7.x does not work well with my computer – as in it cannot see my TiVo, cannot transfer files, cannot share My Music or My Pictures, cannot do anything that it is supposed to.
For clarification, I am running Windows Vista 32 (one of the 200 “Home” editions), and McAfee SecurityCenter, and have tested the TiVo with both its wireless dongle and a hardwire ethernet connection through my Linksys router. Yes, I have all of the appropriate program access permissions granted and all of the necessary ports unblocked. Reverting back to TiVo Desktop 2.6.2 (thank goodness I keep old install files around) seems to have corrected the problem, but if any of my three readers are having similar problems, this could be why.
I cannot seem to isolate the actual problem (end-tasking McAfee (for only a short period, granted) does not correct the problem, and tinkering around with Windows Defender does not seem to fix anything either), otherwise I would report this issue… if anyone has any suggestions, I am certainly open to them.