Problem with crystal report

[mounir_az]

hello.

When i clic "SAVE" formula in crystal report it show me this error:
"A number is required here". and when i clic OK it select me "ABS".

This is my formula:

IIF ({T_stagiaires.cc1}>0,{T_stagiaires.cc1} ,"ABS" )

Are there any solution for this problem ?

thanks