pg_dump version mismatch

I have pg_adminIII 1.8.4 (latest form download siteI am still getting
version mismatch messages running a backup:

C:\Program Files (x86)\pgAdmin III\1.8\pg_dump.exe -h myhost -p 5432 -U
postgres -F c -b -v -f "C:\Work\BACKUPS\postgres.backup" mydata
pg_dump: server version: 8.3.6; pg_dump version: 8.3.0
pg_dump: aborting because of version mismatch (Use the -i option to proceed
anyway.)
pg_dump: *** aborted because of error

Looking at the archives and other sources implies pg_dump should be using
the -i option but I cant see how to set this anywhere.

I would have expected a version difference at the x.x.0 level to be ignored
anyway.

Any advice on how to change this?