I remember in March 2004 my vbulletin forum had 11,000 pages indexed in google. Today it has 9,000. How comes google is droping pages?? Is there anyting I can do to increase the amount of pages in google??

probably they are either too deep in the navigation or they are seen as duplicates.
How many pages show for a site:domain search with and without the dup filter applied?

the site in question is www.mcseworld.com I have just done a site:mcseworld.com in google and it has found 9,350 pages

just duplicate purging. At least 8 versions of the forum pages can be indexed. duplicates Google is deciding which ones they think are important.

ok, Thanks for that, Google is taking there time!!