Go to Record/request/page does not go to a records with a specific value in a field. It puts the focus on a specific record by its specified position in the current found set.
If you use:
Go to record/request/page [ 5 ]
you make the 5th record in the current found set the current record.
To further confuser your results you are using a boolean expression in this step: dbo.accounts::ID = $POID. That expression will either return a 1 ( the values are equal) or a 0 (The values are not equal). Thus, if the result is False (o), you get the error code you have reported.
Instead of new window, you might try using Go To Related Record with the new window option. This will require a relationship (probably a self join) such that you can use set field to put the POID value in a match field and then GTRR can pop open the new window and make the specified record the current record.
It looks like you are trying to set the value of the variable in your go to record statement. Your go to record statement needs the record number you want to go to. You have already set the value at the top of your script. Try Go to Record[No dialog;$POID]