invalid abstime to timestamp error only on specific date range

I have a postgres table with a column type abstime.  (all data in this
database are loaded from an ancient propriety database)

When I filter data from this table with a specific date range on this
column it works.  When I filter with a different date range
it gives me an error like

invalid abstime to timestamp

I don't have that server at this moment and I cannot post exact error.
 I'll if I have to.

I was pulling my hair out because it happens only with a specific date
range and can't be my invalid format in select statement.

Say i do

psql> select * from shipping where ship_date <= '04/22/2008' and
ship_date>='04/21/2008'

it works but if i do

psql> select * from shipping where ship_date <= '04/22/2010' and
ship_date>='04/21/2010'

it won't even perform the query but emits the error.

Both server and client are 8.4.3

I tried other date formats but above format should work because it
works with 2008 year.

Thanks for any suggestion