What exactly do you need help with? Can you please provide some more context and upload a Tableau Packaged Workbook including sample data?
Thank you for your reply Tom. I have actually found a simple solution to my problem.
I simply created a "table calculation" for both 'errors' and 'work hours.' For the calculation type I used "moving calculation," and for "summarize values using" I chose "sum." I then chose 'date' as a value to move along. I did 17 previous values and included the current value, giving me 18 values total to use for my calculation.
After creating a separate table for both 'error's and 'workhours' I created a forumla in the shelf for my final rolling calculation, as stated above.
I hope this helps someone else.