I had trouble enabling punkbuster the other day along with a few other people recently have had the same trouble...
(this all relates to client side not servers)
Once patched with the 1.3 patch if you go to options and enable punkbuster and your game crashes..no need to reinstall the whole game..
(I did this 3 times thinking I did something wrong.)
I browsed to my C://Program Files/Activision/COD2/Main/Players/Default...inside is the mpconfig_mp.cfg. Open with notepad and in the middle you will see the line..seta sv_punkbuster "0" change this 0 to a 1 and then change file properties to read-only.
Then you wont have this problem anymore..
I may be doing this the wrong way..but it worked for me and 3 others.
I have 7 servers streaming...I recall when setting one up {I cant remember the command} once added to the pbsv.cfg it sends a heatbeat to pbbans or something like that... pb_sv_?????..Reason I just added one this morning and it was streaming fine..now it says not streaning..It is empty now..which i think is why....I just like to look and see that its streaming all the time...