disregard it. I figured out by myself.
Can you post your solution, so others can learn as well. ;-)
There are 2 issues. I accidentally remove deploy/ejb2-timer-service.xml. I guess for ejb2 it must exists. (Return it from original zip)
Second issue - application itself need to be rebuild with new dependencies to JBoss5. Old file as is doesn't work.
That is it.