Problem:

Column C contains a formula that divides each number in column A by the corresponding number in column B:
=A2/B2
The formula returns the #DIV/0! error for each empty cell in column B.
When using the AVERAGE function to calculate an average for column C (=AVERAGE(C2:C7)), the errors present within the range prevent the formula from calculating a correct result, and it returns #DIV/0! as well.
Therefore, we want to create a formula that ignores the cells containing #DIV/0! errors when averaging the results in column C.

Solution:

Use AVERAGE, IF, and ISERROR functions in the following Array formula:
{=AVERAGE(IF(ISERROR(C2:C7),\"\",C2:C7))}