Userform-vlookup/submit question

[Skramp]

I have a userform I've developed that has combo boxes that when selected fill a corresponding text box with a vlookup formula. Those work fine but the issue is when you hit the button to submit your entries into the sheet, I get an error because the cycle has started again and with no value in the first combo box it errors out. I have it set to clear the userform after submitting, so what are my options to have it clear, but not error out everytime?

 

[DanteAmor]

You can put all your code