strange, we do replication from SQL 2005 SP 2 to SQL 2000 and no problems. even reinitialized 2 subscriptions last night to some ancient sql 2000 servers we have. even set up some new publications last month from SQL 2005 SP2 on 64 bit to sql 2000. distributor is build 3186 and the publishers are a mix of sql 2005 SP2, sql 2000 and same thing for the subscribers

are you using SSMS to connect to all servers? last year when playing with it i noticed it doesn't like it if you don't use SSMS for everything

i do the following

use SSMS to connect to publisher to create publication

use SSMS to connect to publisher and create a subscription. it will then go to subscriber and create it there

run snapshot

run logreader

and then run the subscription to initialize it

my SSMS is also patched with the latest hotfix from MS for SQL 2005 and uninstall SQL 2000 EM and stop using them to save you the headache. just use SSMS for everything