Oh Hi There!
Wow, you exceeded the number of package names this APT is capable of.
Today we're going to explain this error because it's very alarming for the novice user.
APT is the name of the package management system used on jailbroken iPhones. Cydia itself is a front-end GUI for the APT Package Manager and the version of APT used can only handle up to 65K packages, yes 65,000 packages (source: Brittag, saurikIT) the default repositories add up to 41K, that's 41,000 packages already used up out of the box when you jailbreak. This is perfectly fine, you now have room for an additional 24,000 packages which is quite a few, once you add the insanelyi repo of 7400 packages and growing, this number reduces down to 16,600, but you get the point. The only way to exceed the maximum packages APT is capable you'd have to also add the some of the other largest additional repositories, X,ihacks,biteyourapple,hackyouriphone etc, which is completely pointless since these repositories host 90% of the same content, why do you need 5 of them ? More is not better, all this does is slow down Cydia for you, causes more errors and gives you a poor Cydia experience. I'm sorry, but your not missing out by not adding all these repositories, at insanelyi we try to cover almost everything you would ever want. From deep down in my heart I ask you to please choose 1-2 additional repositories you like and stick with them, smaller additional repositories are fine, reptrich etc, but keep is mind the more you have, the slower Cydia will be.
I really hope this article covers everything, if not please let us know in the comments below, also any questions will be answered in the comments below or you can create a thread on our support forums http://insanelyi.com if you need help with a different Cydia or Repo error you can check out our large thread on them here