Which iPod do you have? Are you jailbroken?
As far as apps crashing on launch, when this happened to me I found out that it was due to my computer that I was syncing, it had not been authorised with iTunes. Reauthorising all devices and reauthorising the machine and re-syncing apps solved the problem. Interestingly the couple of apps I had installed via Installous (which were no longer available on the App Store) launched just fine. Another win for DRM there, keeping honest people honest.