Exclude cells with a defined value from being counted in a formula

Hi All:

I have a spreadsheet ( see attached ) which tracks the Corrective Actions for my Quality system. The formula in cell AE3 calculates the % of corrective actions closed in 30 days or less. My problem is that it counts all cells, I want to exclude cells in column "F" that contain the value "Vendor Error" from being counted.

Any assistance is greatly appreciated.