>I have a complex iif() line in the dynamicforecolour property from a grid.
>The iif() command is not working.
>But i do not recieve an error and i cant find the error in the line.
>How can i test where i make an error.

In those situations, I would try to make it work from the command prompt. However, if that is not possible, I would try to test the line at its simpliest form and build from it after until I find which part is bugging.