tsearch2 column update produces "word too long" error

Hello!

I'm currently testing deployment of tsearch2 on our forum table. The
table is huge in itself - some 2GB of data without the indexes. I have
got PostgreSQL 7.4RC2 running on a test machine, installed tsearch2 to
my database, added the new column to the table and tried to update it in
the recommended fashion:

UPDATE ct_com_board_message
            SET ftindex=to_tsvector('default',coalesce(user_login,'')
||' '|| coalesce(title,'') ||' '|| coalesce(text,''));

It does run for a while but at some point I get "ERROR:  word is too
long"; I guess that this is caused by some idiot user(s) writing some
Joycean nonsense (but most probably without the literary value) or
drivelling about their holidays in
Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch (Wales). Now
what could I do in order to intercept this error?

Kind regards

    Markus