Using Avant for browsing is virtually the same as using Internet Explorer I understand-as that is what it is "under the hood",and it does not make an easy task for Eraser owing to a locked file. To quote the Eraser Help File "Please notice that what you see in Windows Explorer when viewing the Temporary Internet Files or History folders is not the actual directory contents, but an image built from index.dat database file, which is kept locked by Windows shell and cannot be erased."
I do not know the level of security or privacy you require,but there are plenty of free applications for erasing IE,and some include the locked files mentioned.Another way is to use the free(ad.supported) version of NetCaptor,which is broadly similar to Avant,and has a "Clean Up" facility to erase/wipe up to nine browsing tracks,including the locked file mentioned above.Better still(for many other reasons!),use Firefox,Opera or Mozilla-all easily dealt with by Eraser! Opera,it should be noted,has an admirable and comprehensive "Delete Private Data" tool to cover a similar requirement.