I am running Slony 2.0.2 replicating tables from an 8.3 cluster to an 8.4. 
The following scenarios has happened consistently:

1. Issue SUBSCRIBE SET
2. Slon log on receiver goes into loop due to "transactions earlier than XID
nnnnnnn are still in progress".
3. A few minutes later, the long query on the provider node is finished.
4. Slon on receiver now tries to copy the set, but gets 
   "ERROR remoteWorkerThread_7: Could not lock table "public"."abc" on
subscriber"  where abc is the 1st table in the set.

It will loop like this indefinitely, until I bounce slon, then it works.
Also, at the same time that error happens in the slon log, I see this in the
Postgres log on the receiver:
  LOCK TABLE can only be used in transaction blocks.
  Statement: lock table "public"."abc"

This is very consistent.  It's not a show stopper, just annoying.  I don't
remember this in 2.0.1.
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