It's SQL0312 reason code 6 again

SQL0312 errors are making me crazy. Variables are being interpreted by the
precompiler as constants.

I'm defining variables like this...
dcl-ds FRP010 ext template qualified end-ds;

dcl-s dscode like(FRP010.dscode);
//Line/commodity cod
dcl-s dsseq like(FRP010.dsseq);
//Group description

Unless they changed the rules, DCL-S means "variable" and these fields are
not tagged with CONST. Today the compiler thinks they're constants (in the
compiler cross-reference). Friday at 1800, it didn't, and I have the
compiler listings to prove it. Using RDi to compare source has revealed no
changes (I assumed I had lint in the source somewhere). And *previous
versions of this program will not compile.*

What's driving me crazy is the 500,000 lines of SQLRPGLE code that use
these same copybooks and program design--they used to compile. And I've
even pulled out my data definitions, replaced them with DCL-S, and I get
the same compiler failure. Two of my major programs--order entry and rate
quoting--won't compile. But others, using the same copybook and SQL logic,
do compile.

Columns that aren't referenced aren't defined incorrectly as constants.

I'm hoping my customer will tell me they applied PTF's over the weekend.
If not, I am S.O.L.

I'm grateful for suggestions.

--reeve