Rooted, can't install non-Market apps

Running stock Froyo on my Captivate (Firmware Version 2.2, Baseband version I897UCKB1, Kernel version 2.6.32.9, Build number FROYO.UCKB1). Want to be able to install apps from Amazon so I rooted, using SuperOneClick.  Went through both the Root and Shell Root setups, and my phone is rooted.  However, when I run the Allow Non Market Apps I don't get any sort of confirmation.  It just runs for a while then stops.  Doesn't say that it failed, but it doesn't say it was successful, either.  When I try to install apps from Amazon they download, but fail on the install with the "non-market apps not allowed for your security" message.  Any help is appreciated.

Phone is rooted with SuperOneClick.  After rooting, I ran the "Allow Non Market Apps" option on SOC.  There is no Allow option under Applications to check.  I now tried to install an apk from my Dropbox and it gave me the non-market apps not allowed error.

I did a Factory Reset (Start>Menu>Privacy) AND a Factory Format (GSM Reset) before running SOC.  I still get the security error when I try to install anything from Amazon or from my Dropbox.

I have superuser status.  i have mybackup pro and it is able to backup apps and their settings, which is only available if rooted with superuser status.  tried to reinstall apps i downloaded elsewhere (amazon, etc) and have in my Dropbox.  Those fail when I try to install - get the non-market security message.

The only thing I can do is sideload with SideloadWonderMachine.  It works, but it's more work than just downloading and installing.  The main/only reason I rooted was to be able to install non-market apps, to avoid these extra hassles.