Normally when install0us comes up with an .ipa error you should reinstall appsync and install0us. That's what Ive seen from looking around the internet. But be careful with install0us it can cause problems because it is not from a trusted repo. It should work but make sure to use it "clean" by not over-downloading and if you have iwipecache or another similar program it might help to keep your phone running smoothly.
im not a veteran jailbreaker, but this is what i do and it seems to run ok.
the only problem i have found is when downloading a game not all of the DL links work. so if a game doesnt have any DL links working try to ssh an .ipa onto your phone instead. this can be tricky but i found a link that can help:
Adding ipa's With Winscp and SSH - SiNfuL iPhone
hope this helps - i know nothing has been posted on this thread for a while so i hope you see this.