This function is activated as part of DIPSYSFNC, the DIP script run when DIP ALL is run. But the DIP script does not grant rights to TD_DBQLParam. DBC must be explicitly granted rights. For example:
GRANT EXECUTE FUNCTION ON TD_SYSFNLIB.TD_DBQLParam TO DBC WITH GRANT OPTION;
For queries that have parameter markers or positional parameters with question marks (?), variable names are replaced with proper names only in DBQL ParamInfo logging to P1 through Pn. P1 through Pn stand for the positions of the parameters in the query text, reading from left to right.