You have used the Where condition in your command.
What that does is force Access to FIND a record that satisfies the where clause. It does not Create one.
If you want to pass data to a form then you can use the Openargs parameter :
DoCmd.OpenForm "SystemErrorMessage", , , ,,, Err.Number & ": " & Err.Description
Then in your SystemErrorMessage form you can assign the value.
If SystemErrorMessage is an unbound form then you can use the form load event procedure:
me.lblTitle=me.openargs