You may find it’s not so much a problem with Avast as with cftmon.exe. It is reported to cause issues with several applications, see here for an example:
http://actualtools.com/forum/read.php?FID=9&TID=63
and also this very informative article on it with so9lutions:
http://www.howtogeek.com/howto/windows-vista/what-is-ctfmonexe-and-why-is-it-running/