That's not the error from the docs, Johan.
The docs refers to illegal use of a private property.
And it looks as if Bruce has changed to a workaround to try to avoid the requirement to edit abfile.inc.
The code in the doc references the (protected in old versions) property directly: RM.Me.HasAutoInc = false
The code in your example (and in 12.37 I just downloaded) uses a METHOD rather than looking for the protected property: GetHasAutoInc()
Looking at abfile.inc, my version of clarion 10 (10.0.12349) DOES have a method called GetHasAutoInc.
Looking at abfile.inc in clarion 9.1, the property HasAutoInc byte,protected exists but the method to retrieve it (GEThasAutoInc) does NOT exist.
So I'm guessing that the method was added to C10 some time after your version.
netweb.tpw for 11.37 on line 341 is checking for clarion versions less than 10 and assuming that higher versions DO have the GetHasAutoInc() method. But apparently your version of C10 does not.
Since you've removed the PROTECTED attribute from the property in abfile.inc, you could probably change the code in your screen shot so it again reads like what is in Bruce's doc page and check the property directly:
If p_forceWrite and RM.Me.HasAutoInc = false !8000
I'd make a backup copy of netweb.tpw and alter the code between lines 341 and 349.
Cheers,
Jane