create tables in empty database (libpq)

Hello,

I'm trying to create tables with libpq in an empty database.

The database named 'cash' is created with 'createdb cash'.
Then connecting with libpq is ok but i can't execute any
queries. After procssing a query PQresultStatus gives the
error message :
   PQresultStatus() -- pointer to PQresult is null

Tying to disconnect the database with PQfinish gives a
segmentation fault.

Any suggestions how to fix this ?

Thanks in advance,

Henk Jan