Name checkbox with vba

Dear forum,

In a userform are multiple checkboxes. The come in sets of two (yes or No)
If a checkbox is clicked (true) then a cell value in sheet1 = "yes"

Upon 'Initialize' I want the backcolor of one of two checkboxes to change.
To do this I've assigned an ID to every couple of checkboxes
For example:

HTML Code: 

The checkboxes in the userform are cb1 and cb2 etc.
When running this code I get an error 91, object variable with, etc..

Please help.
Or is there a better way to do this? Sure there is, however....

Regards, Rudy