Null pointer or function not found

CloverDX Platform
1

Non-autogenerated functions cause “Error: null pointer or function not found”
Any functions not generated by the tool give me the following error:

Caused by: [Error: null pointer or function not found: toString]
[Near : {... l(input.S) ? null : toString(1234)); ....}]

I tried something very simple and the first line fails but if I comment it out it works.
Also if I use one of the other functions like str2date it also works.
Why?

output.CreditAmount = (isnull(input.S) ? null : toString(1234));
output.BatchId = input.A;
output.DistributionReference = input.P; 
output.TransactionDate = (isnull(input.F) ? null : str2date(input.F, "MM/dd/yyyy"));
output.GL_AccountNumber = (isnull(lookup(LookupYoungYouToGL).get([input.Q])) ? null : lookup(LookupYoungYouToGL).get([input.Q]).GL_Code);]]></attr>
2

Hi,

We have analyzed your code but we miss some details, for example declaration of “input”. Can you please provide us with:

* version and edition of CloverETL you use
* complete source code of transformation causing this issue (you can minimalize it to core problem)
* complete error message, including stack trace

Thank you!