While the compiler error Norman discovered earlier was related to the change I made yesterday while investigating another issue, that change was not at fault. (That change had, in fact, been removed.)
While a great deal of attention has been paid to the assignment of line patterns, somewhat less attention has been paid to removal of them. And, it turns out, should a line pattern have been removed - even temporarily - it left the line in a state that would "upset" the compiler. (It appears to have been such a line that caused Norman's issue.) While you could have detected something was wrong on subsequent edits of the line, you would have had to look hard to see it.
Tomorrow's release of ADE_GP will contain not only a fix for that problem, it will also include some code in the GP Editor that will automatically detect and rectify the issue on lines where it exists. Unfortunately, I was not able to apply the latter to the "silent edit" that precedes the compile (so that all such errors would have been corrected automatically), but the compiler will now tolerate the situation.
So, should your compiled GP Lines not be properly textured, all you need do (with or following tomorrow's release) is re-edit the line, close the GP editor with OK and recompile.