Problem with driver

I keep getting this error:

Database error in EmbeddedData.fetchData Invalid character data was found.
This is most likely caused by stored data containing characters that are
invalid for the character set the database was created in. The most common
example of this is storing 8bit data in a SQL_ASCII database

with current postgres drivers downloaded from
http://jdbc.postgresql.org/download/ (like pg73jdbc3.jar and others). The
error is only thrown when I try to access one table (other tables in the
database work fine).

However I don't get this error with pgjdbc2.jar, which I downloaded about 8
months ago.

I will appreciate any help to resolve the problem. I really need to use new
features in the updated drivers.