In addition to what the other monks have suggested, considering you are new to the website, if you fail to find a solution, can u isolate the section of code that is causing you trouble and update your question with a small script with necessary instructions/env details, in a way that one of us can quickly run your script ?
Looking at your question, you dont seem to have a problem with steps 1,2 4,and 5. The issue seems to be when moving from Step 3 to Step 4 i.e when you are trying to move data from your Tk dialog to your DB (select)?