ASMA127S Illegal use of ampersand

Explanation
One of the following errors has occurred: 

An ampersand was found where all substitution should have already
been done

The standard value of a keyword parameter in a macro prototype
statement contained a single ampersand or a string with an odd number
of ampersands

An unpaired ampersand occurred in a character (C) constant

System action
In a macro prototype statement, all information following the error
is ignored. In other statements, the action depends on which field
the error occurred in. If the error occurred in the name field, the
statement is processed without a name. If the error occurred in the
operation code field, the statement is ignored. If the error occurred
in the operand field, another message is issued to specify the default.
However, if the error occurred in a C-type constant, the operand in
error and the following operands are ignored.

Programmer response
Ensure that ampersands used in keyword standard values or in C-type
constant values occur in pairs. Also, avoid substituting an ampersand
into a statement unless there is a double ampersand.

Severity
12