layout problems with Compose PM screen

[The FlyerFly]

I am using a heavily modified version of acidtech, and the only layout issue i seem to currently have is in the Compose Private Message screen. the composing field is bleeding over into the sidebar. it seems like a simple width issue, but i cant figure out how/where to change layout values for this screen.

Can you help?

here is a screenshot...

http://flyerflies.com/images/screenshot2.jpg