Recently a few people have reported that their McAfee Virus Scan is detecting trojans in the miro install and uninstall executable files. This is another instance of McAfee getting false positive hits against the NSIS installer.
NSIS has a page on their wiki which they keep updated. You can find it here: NSIS False Positives.
False positives are always annoying.
Hopefully Mcaffe will fix it soon.