Dave, I think I see the problem. When I open the structural .c2s file it expands the files so that the _x shows up. When I exit the structural preprocessor Caesar II then 'zips up' the files back to the c2s. Thus when the .CAESAR II piping input file opens it can't find the _x. By copying the _x and other expanded structural files to another directory while the .c2s file is open, then closing the c2s, then copying the _x back and other structural files back into the original directory, and then opening the .CAESAR II piping input file, Caesar II then recognizes the _x.
Is there a simpler way?

Wayne Dolbec
Middough