Database Problem

When I drag a database table field from my data sources tab in visual basic and drop it onto a textbox object on a windows form and run the program I get the following error;

Type BolInvoice.BolInvoiceDataSet is not defined.

BolInvoice is the name of my form and BolInvoiceDataSet is the name of the dataset.

I click on the error message and it takes me to a line of code that says;

Me.BolInvoiceDataSet = New BolInvoice.BolInvoiceDatSet

If I delete BolInvoice. from that line of code the program will run until the next time compile and the the same error message pops up.