Thanks Keith.
I downloaded the GC-Prevue and ran the program. It does not like the .CAM and .gpi files that Eagle created. But it works for all the other files and it gave me the display of all the layers I want and they look fine. What are the .CAM and .gpi files? This is step by step how I create the gerber files. Can you take a look and see whether I am doing it correctly?
Gerber file creation:
1) Open brd file. Click File, CAM Processor.
2) Type name (Alan1) in Section.
3) For all files other than Drill, Device is GERBER_RS274X. For Drill, choose EXCELLON.
4) Do one file at a time start with Alan1.top for top layer. Click Layer on top and choose clear all. Then choose top, pads and vias only.
5) Click File, select the path when to generate the gerber file. Then click ADD at the bottom.
6) You'll see Alan1 on the tap, click the last tap on the right. Then change the extension to .bot for bottom layer.
7) Choose bottom, pads and vias on the right, then click ADD at the bottom.
8) Click the right most tap at the top, then change the extension to SST for silk screen top. Clear the selection and click Dimension, tPlace, tName. Then click ADD at the bottom.
9) Click the right most tap at the top, then change the extension to .SMT for solder mask top, clear the layer selection and click ONLY the tStop only. Click ADD.
10) Click the right most tap at the top, change the extension to .SMB for solder mask bottom, clear the layers selection and click ONLY the bStop only. Click ADD.
11) Click the right most tap at the top, change the extension to .DRILL for drill ( don't use DRL). Choose Device to EXCELLON, clear the layers selection and click DRILL and HOLES. Click ADD.
12) Save the file by click File, Save As, choose destination and call the file name Alan1.CAM, save.
13) Click Process Job. All the files will be saved in the designated folder.
View Gerber using GC-Prevue
1) In File, click IMPORT.
2) Go to destination folder and choose Alan1.top, .bot, .SST, .SMT, .SMB, .Drill and click Open.
3) Don't choose .CAM and .gpi as they gives error.
Why do we choose EXCELLON only for the drill file and GERBER_RS274X for the other?
Thanks for all your help. I think I have done a complete go around from creating parts, creating schematic, boards, CAM and view. If there is anything I missed that is important, please let me know.