no, ati's mobility cards are only supported for a small amount of manufacturers by ati itself. others (like HP) have their own drivers. since theyre far behind of whats up-to-date (last hp driver from early 2008, and last ati driver is from june 18) and deliver significantly poorer performances than original ati drivers (and cause sometimes errors, too), one has to use modified drivers - best choice using mobility modder since it is applied to original desktop drivers of the corresponding card.
this is what ive done, but there are so many errors all the time.. i also looked at the steam support sites (steampowered.com) - for exactly those errors i experience they recommend "updating video card drivers" - well, id like to do that..