type mismatch error

[roubesh14]

Hi guys. I' am getting a problem concerning date.

dateborrowed = pbRst!borrowdate 'where dateborrowed is STRING and 'borrowdate is of type medium date in the mdb
               
expecteddate = dateborrowed + rst!VCDayslimit   'Where expecteddate is 'STRING VCDayslimit is of type number in the mdb

When executed i get a type mismatch error

How can i fix this please
btw iam on vb6,database:ACCESS and connection adodb

thank u