We have received many emails telling us that 90Droid disappeared from the Android Market or cannot be accessed after a Froyo update.
Unfortunately, we don’t really have control over the delivery of the app (downloading and installing it). That is controlled by the android market. Please contact them using their support page: Android Market Support Page
They are usually pretty good at resolving any issues.
Doing a quick google search, I found the following thread that discusses possible solutions http://www.google.com/support/forum/p/Android%20Market/thread?tid=0b929effaf6c8573&hl=en
I hope this helps, let us know of any other concerns you might have.