problems wth rar,zip files

hello everyone
when try to download a rar or zip file my download fails at 99%,when running comodo antivirus
when i turn antivirus off and redownload it does with no problem
have ran antivirus scan and spyware scans with nothing unusual
do you think i should uninstall a/v and reinstall and see what happens

thanks in advance

ps have xp hope running sp2,comodo firewall,antivirus,boclean & spysweeper
have tried turning each one off but it only works when a/v is off