Urgent help needed Question on PQexec

Hi ,

I was facing a strange problem and would be extremely glad if some one could
help me out .

I am using PostGreSQL 7.1 . I know its an old one but our product works on
this & the management is reluctant to upgrade.
Here i am seeing that for one particular query the values are not getting
inserted into the database . However the strange thing is it does not throw
an exception . ( We do have exception handling in place ) . However if i log
into the db & manually insert it into the database it goes through . I am
confused . Is it because of PQexec failing . ? I read that PQexec fails
only when a ) there is no memory ( what memory , how can i check ) b ) when
the connection with the server is not being made . Can anyone help me out
with this problem .

also additionally while creating the database . If i have a column as
character varying (n) what happens if the n is exceeded . Can this be
realted to the above problem .

Please help me .

Sumeet