Add null values to the Database table

Question

Hi,

I have a group box, that contains 5 text boxes and 5 masked textboxes. I wrote the code when user enters the data into all controls than user clicks button, the data saved into database table.

Here is my problem:

when the user doesnt want to enter data  into some textboxes.I want to add it into the database with out any error.

Actually my present code giving me error if user leaves one text box also. 

How can i do it?

Darma