Plot Style (ctb) file won't work

I have been plotting perfectly fine in AutoCAD 2000i for years. (We are nowusing Land Developement Desktop 2i, but that shouldn't have to do with this problem.) Now, we go to plot, set all the plot settings including the ctb file, but when we preview the plot everything is shaded according to thedarkness of the color. This does not correspond to the Plot Style (ctb) file setting. A 'work-a-round' that we have discovered is, once opening autocad, goto Options>File> and then just simply pick on the Plot Style Search Path that is saved. Don't change it, just pick it. Then go back to plot, do a preview, and then all the colors appear to correspond to the ctb file. This is odd and a major neuscense. Even though the Plot Style Search Path is saved in the Options>File tab, we are forced to open this Options dialog box everytime we open autocad so we can print correctly. Nothing is changed, but we simply have to pick on the file path that is already saved. Any suggestions or fixes? Could this have something to do with loading a profile?