I can't download with Installous because it keeps saying invalid IPA?

Hello. I just jailbroke my iPhone 3G yesterday by myself using my computer with the program redsn0w. I downloaded Installous 4 through Cydia. I managed to download and install WhatsApp, but I have been problems downloading other applications like "Surviving High School", "Cooking Mama" and "I Am T-Pain" because they all say "invalid IPA" after downloading so I can't install them. Whats more, I tried looking for more sources but theres no more, so I can't download any. Everyone is saying to download Appsync thru Sinful iPhone Repo which I did. But everytime I want to download Appsync 3.0+ whatever, it keeps saying it cannot comply and asks me to queue it. Then when I try to download Appsync iOS 4.0+ with Sinful iPhone Repo, it can be installed but it keeps returning with an error code and I can't download the applications I want. Please help!