I got the same message this morning from my computer (WinXPSP3), for the same file: C:\Program Files\Common Files\InstallShield\Driver\11\Intel 32\IDriverT.exe, 69,632 bytes, file version 11.0.0.28844, unchanged since April 2005.

I uploaded it to VirusTotal, where all 47 AVs (including Avast!) called it harmless. -JW