On Mon, 09 Feb 2009 19:07:19 -0600, wrote:

I've always used powder dishwashing detergent in past


Don't use powder.

But for some reason I bought some gel detergent to try
out

Tow days after using it my dishwasher (albeit old) just
up and quit. It does act as if the drain system is
plugged up.

Could it have been the gel detergent? Possible?

Yes if it caked the powder. Run the unit several cycles hot
waterwithout any detegent and try to flush the drain pipes.