Retrieving a recordset based on a combo box selection

I have a user select from a combo box that was populated from an Access database.
I then want to call the rest of the recordset but my seek function will not work like I remember.

Here is what I am working with:
I get this error in debug mode:

"Run-Time error '3251':
Operation is not supported for this type of object."
When I click Debug, it highlights this in yellow:
My data control(datRoute) is set to dynaset

I remember being able to pull a recordset using a text box and then using the seek function
I cant seem remember how to do this part.

Any help would be greatly appreciated.