i c that u have, well, succesfully, uninstalled mcafee, and r now using avast.
even on successful uninstal, several programs leave behind such dll's, which are refered to as "orphaned dll's". re-verify from the properties of these mc* dlls that they r indeed mcafee files, and then safely delete them.
for addl info click
how to remove orphaned dll's ! and carefully read

all the posts.
addtnly use
ccleaner to clear ur residual pc junk.