C.1.42. Error 46 - Invalid variable reference.

Explanation:

Within an ARG, DROP, EXPOSE, PARSE, PULL, or PROCEDURE instruction, the syntax of a variable reference (a variable whose value is to be used, indicated by its name being enclosed in parentheses) is incorrect. The right parenthesis that must immediately follow the variable name might be missing or the variable name might be misspelled.

The associated subcodes are:

001: Extra token ("token") found in variable reference list; ")" expected.
900: message.
901: Missing ")" in variable reference.
902: Extra token ("token") found in USE ARG variable reference; "," or end of instruction expected.