Inserting NULL values with the embedded driver

[Robert Enyedi]

I have an application that runs on Derby with the network JDBC driver. 
When I switch to the embedded JDBC driver my aplication fails because I 
receive the following exception when inserting a NULL value in a VARCHAR 
field:

"An attempt was made to get a data value of type 'VARCHAR' from a data 
value of type '0'."

Did anyone encounter such a strange error?

Regards,
Robert