Zenon Logic error

Zenon Logic error

Hi all.

I tried to use this statement in yenon logic:
R.Step[0].Phase[0] := ...

Error message appears:

Build in progress... Please Wait...
 C:\ProgramData\COPA-DATA\SQL2022\561184b2-8848-4df1-be3c-6f8c6c28e543\FILES\straton\ZLogic
Compiler V14.0.49.79
>> Complex variables stored in a separate segment
Loading application symbols...
main
main: (164): R.Step: Unknown identifier
Error(s) detected

What can be the solution?
I suppose that brackets are the problem?