Can any one let me know how many “if ()” statements you can have in a derivation formula ?

I have been trying to get below working and think I may be missing something.

if( ProductCode = blank , "PNL.tif" ,  if(ProductCode not = any rFM_Link ProductCode, "PEVC.tif", if( ProductCode = "Special.******" , "special.tif" , concat( ProductCode , ".tif"))))

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Whats Working !

if( ProductCode = blank , "PNL.tif" (WORKS)

if(ProductCode not = any rFM_Link ProductCode, "PEVC.tif" (WORKS)

if( ProductCode = "Special.******" , "special.tif" , concat( ProductCode , ".tif" (NOT WORKING)  

it's not the number of if() statements which is the problem but the length of the derivation. In 6.x it is only 255 characters. In DE8 it is 4096.

Thanks for your reply, I see what you mean, but on counting the carectors including spaces I make it 184 Number used, so should be within the 255 number, or am I missing the point ?

Sorry, but is this a derivation in a field?

You can't use "any rFM_Link ProductCode".

In derivations you need to use Lookup.

Perfect thank you, "Lookup" makes the form work now as expected. 

I have another problem popped up, luckely I backed up before it occurred, "Access Violation" on one form  Please see attached, before I restore is there any way of overcomming the error ?