>Your stack trace shows a call to CopyToDataTable, but nothing in the code you posted appears to be calling that.

I guess I was wrong in the identifying the source of the error originally. It seems to be happening on this line

dtResources = dtReturn.Select("", orderBy).CopyToDataTable();

dtReturn is empty in the debugger.

So, I added an extra check for Rows.Count = 0 to fix it.