Extrusion relevant for lines?

Hi,

I have a particular DXF file which has several lines, arcs, and
polylines which have extrusions associated with them.

I'm reading this DXF file with my own converter program. I've
implemented the arbitrary axis algorithm and have had multiple success
stories using it.

Now the strange part. When I read a polyline from this file and get
the extruded polyline everything seems to convert just fine.

But, same algorithms mind you, when I read a line entity from the file
and get the extruded line the resulting coordinates are not correct.

When I comment out the code which reads the extrusion values for a
line then the line's coordinates are suddenly correct.

Even though AutoCAD documents extrusion values for line entities,
should they be ignored? Is there some line entity code I'm missing
that says skip the extrusion values?

I'm afraid to start cutting code from my program since it has worked
so well in the past. But, I cannot with any certainty say I've read
other DXF files with extruded lines. I can say with certainty that
I've read other DXF files with extruded polylines.

BTW, I don't own AutoCAD, but I do have TurboCAD and it reads the DXF
file just fine as well as the VoloView program.

Thanks,

Zac