In the Event "Displaying a row of the Table control" of your Table-Control use something like this:
SWITCH Modulo(MySelf,4)
CASE 0
MySelf[MySelf]..BackgroundColor = LightBlue
CASE 1
MySelf[MySelf]..BackgroundColor = LightGreen
CASE 2
MySelf[MySelf]..BackgroundColor = LightRed
CASE 3
MySelf[MySelf]..BackgroundColor = LightYellow
OTHER CASE
END