Samsung Vibrant : Market Download Unsuccessful - Then Unable To Reset

Long story: Went in, got my Vibrant, immediately downloaded a few apps to play/test the device in the store. I got handcent and barcode scanner. Went home, tried rooting phone, couldn't get into the recovery menu. Gave up on rooting for the moment and tried to download launcher pro, and immediately after it started the download it gave me a "download unsuccessful" error, regardless of whether I was connected via 3G or Wifi. I then tried downloading several other apps and got the same error. Afterwords, I tried clearing the market's cache, signing in/out of Google Talk, uninstalling the apps I had originally downloaded, rebooting the phone; nothing worked (and I was unable to reinstall the apps I had managed to install in the first place, due to the same error). I then attempted a factory reset and was unable to do that, given the error "No reset was performed because the System Clear service is unavailable." After going through tech support through everything I did, they asked me to do a hard reset of the phone, which I didn't realize used the same recovery menu as one must access to root the phone. Since I couldn't get into the recovery menu for whatever reason (I blamed my fingers at the time), I was told to go back to the store to swap my phone out for a new one. Did that, repeated the app downloading process but didn't connect it to anything other than a car charger, and the app store gave me the same error, and I'm again unable to perform a factory reset or a hard reset. I know it's not my fingers, though, because I was able to get into the recovery menu of a display phone at the store.I'm going back to the store tomorrow to swap my SIM out, since tech doesn't know what else to do with it, but I was wondering if you guys had any input.Short story: First symptom was all market downloads failed with error: Download unsuccessful. Second symptom was inability to perform a factory reset or a hard reset. Possible causes/solutions?EDIT: Problem seems to have been fixed by going to Settings > Applications > Manage Applications > (menu) > Filter > All > Download Manager > Clear Data. Will update if anything fails afterwards.