NULL feilds and ERROR messages from libpq++

Okay, I need to generate e-mails based on a table that may or may not
have certain fields that are null. Why is it that every time I do a
PgDatabase::GetValue on a field that has a null value, I get an error
message printed to my console ("PQgetvalue: ERROR! tuple number 0 is
out of range 0..-1")? Is there a way to turn this off? If
not, what is a good work-around?

Thank You,

Tabor Kelly