Formula worked in Excel 2003 but doesn't in 2010.

When I used this particular formula (in P29 on each golfer's sheet) the past few years, I was using Excel 2003. Now I am using 2010 and the formula to determine a golf handicap doesn’t work. I have between 0 to 16 weekly TOTAL scores for each golfer. I need to find the best 5 out of the last 10 to figure the final handicap. In the past, the scores filled rows 12 or 13 to 29; this year my scores ended on row 28. I thought I could just change the 29 to 28 in the formula and it would work but it doesn’t. Why? You will see that I changed the formula (in P29) for Anderson and Arnold to 28. The others are the original formula with the 29. There is an ! (that pops up in O29) saying, a value used in the formula is of the wrong data type. I don’t know what that means. I have attached my spreadsheet.

I'm sorry I didn't explain myself well. I thought I had attached the entire workbook and indicated what the "!" in O29 (if that is a code) showed on my screen. Thanks for your help. It works fine now that I changed the 29 to 28 and did the ctrl+shirt+enter.