VMS Help CC, Messages, NOCOLONINEXPR  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Message        Missing colon for conditional expression.

 Description    A conditional expression that occurs as part of a
                preprocessing expression was missing the ":" that
                separates the second from the third operand.  The
                value of the resulting expression is undefined.

 User Action    Correct the conditional expression.