I use Ifeatures, try the following...
http://www.cbliss.com/inventor/Parts/Plumbing/plumbing.htm
The npt feature is at the bottom - You may need to move the "end of part" to the end in the model tree
I had this also
All my text & dims are colour 12 (red-ish) with a black background.
What i have done is put
^C^C-layer MAKE 0;
in front of the text editor callup command ( I use a universal text editor that edits all text i.e. attributes , dims , mtext , ect) theory should work for any...