This is an issue that started as a different problem all together. I thought I had it solved with some help From CK and Tallica, but it's come back again and again. It started in this thread Constant Sync Icon...draining battery...
I figured that I should start a new thread since the title of that one doesn't describe the issue any longer.
So after everything in that thread, I still can not install apps from anywhere, including TiBu. I've done everything from clearing cache and data from the Market to un-rooting and RSDing back again twice. I cannot figure this out for the life of me. An app will download, and just hang forever at installing until I FC the Market or TiBu. It almost seems like I have a corrupted installer. It did work properly after I re-rooted to stock 22D (thanks Motochache1) for about 15 minutes, and then it crapped out again. I was able to install from the Market and from TiBu before it stopped again.
Possibly related, when the issue starts, I can no longer access apps on my SD card. I also can't mount the card to the computer, nor unmount it from within the phone. I have reformatted the card already, and it can be read with no problems from recovery. I can also access all pics on there from the phone, so I'm fairly certain that the card itself is fine.
I'm not sure if it's a permissions issue, or and installer issue, or a hardware issue (although it should never have worked at all if this is the case). If I can't figure it out, I am going to call VzW and have it replaced since I have time left on the manufacturers warranty. Any help with this would be greatly appreciated by my family as they have been missing me since Friday