If by wobble, you mean a front to back movement of the blade as it moves up and down, some movement is built into the mechanism and I don't think it can ever be completely removed. In come cases it can be reduced.
Raising the rear of the table has helped some and has been discussed on this site. Here is one reference
http://stevedgood.com/community/index.php?topic=12146.0Rick's scroll saw site
http://www.scrollsaws.com/ has some ideas as well. On the left menu, click on "Dewalt Tuneup".
I raised the rear of my table and moved the lower rocker mount towards the front of the saw and reduced the movement of the blade to about 1/32".
It's a bit of trial and error but it can be done. When working on moving the lower rocker mount, be careful not to strip the screws that go into the rocker arm. It's easy to strip the threads in the aluminum (personal experience
) - then you will need a new rocker arm.
Let us know your results.
Jim