The "black screen/Finished" phenomenon is, in all probability, caused by "artifacts."
I used to have all of the problems everyone describes, from black screen to frequent crashes, UNTIL Halloween this year!
The day before Halloween, the internal hard drive on my iMac froze solid.
I had it replaced with a new (slightly larger, +25gig, and slightly faster, 7200 RPM vs 5400) hard drive which had 10.6.5 pre-installed on it. I then restored the rest of my system from Time Machine.
Then I re-installed CrossOver Games and downloaded a "fresh" copy of LOTRO from the "games.on.net" website and installed it using the C4P installer.... and viola! I have had zero problems since then. And LOTRO runs "zippier," with higher graphics settings than ever before.
I realize the solution "wipe OSX and re-installm everything" is a bit of a drastic step, however, it is the second time that solution has "worked" for me. (But, I must say, Time Machine now makes the recovery virtually painless - some preferences get lost.)
I had been running LOTRO on my MacBook Pro under 8.1.4 with no problems. The MacBook Pro had originally been a Tiger machine upgraded to Leopard, then to Snow Leopard. When I started working with 9.0 (beta) I could NOT get it to run at all. Finally after several weeks working with Codeweavers support, I bit the bullet, wiped the MacBook and did a clean re-install of Snow Leopard. Since then, I have had no problems with LOTRO on the MacBook Pro.
Since my college-aged son used the MacBook pro for all kinds of "video stuff," both paid for and freeware, constantly installing and deleting things, my working theory is that some "artifact," a piece of "something," did not get removed, and "it" conflicted with the WINE environment.
I've been in the business of System Administration for more than 30 years and have worked with virtually every version of Unix(tm) ever created -- for every different hardware vendor's platform -- and know that while they are all "similar," they are all different. Tracking down the bugs caused by those differences is almost an impossible task -- even when you have access to the source code and developers for all of the parts in hand... doubly so when you are running via something like WINE (CXG), it just adds another layer of complexity.
In short, we (LOTRO Advocates) keep hunting for "solutions" to these various issues, but more often than not, we simply have no "known state" to work from. Everyone's system is different. The "solutions" we come up with "should work," but often they do not. Why we do not know. In fact, we frequently have no idea why they DO work in the first place.