tsearch2 errors after db move

I recently moved a database to a new machine:
  PostgreSQL 7.4.7 on i386-portbld-freebsd5.3, compiled by GCC cc (GCC)
3.4.2 [FreeBSD] 20040728

any queries related to tsearch2 give me this error:

ERROR:  cache lookup failed for function 17188

I am running the same versions of Postgres, Freebsd, etc

I guess my next move might be to run untsearch2.sql on both machines,
do a new dump , and try to rebuild tsearch2 from scratch on on both
machines

Unless someone knows better?