#DIV/0! Error

Hello,
I'm having issues in that I'm receiving a #Div/0! error in my spreadsheet. The goal is to figure out what the final sick and vacation pay would be in cell B15. All green boxes are what the user would fill in and the rest are formulas. Some employees at the company have 2 positions which have 2 different rates of pay. And with that, cell E11 and E12 is the percentage of their job at that particular rate of pay. If there is someone that has one position I would take out the salary in cell B12 and the FTE in cell E12. When I do that, that is when I would receive the #DIV/0! error. Any ideas on how to fix this? Thank you!!!