psql -f backup.out || file too big

Hello everybody!

I am trying to restore a 2.5 Gb. backup file made using pg_dumpall, and I get 
the "file too big" error message from postgres

what can I do to solve this? is this a bug? I have 18 Gb. free disk space, a 
two PIII processor machine with 1 Gb. ram, running Red Hat 7.1 with 
Postgresql 7.1.3 (installed from official rpms)

thank in advance for your help!

greetings!

Jorge Sarmiento