Error "Invalid project description."

If you guys ever run Eclipse or Flex Builder and got the "Invalid project description" message, it usually means you guys are trying to import an existing project into a workspace; moreover, you are trying to import an existing project into the SAME directory path as the workspace.

So if you are in workspace with this path:  
C:\Projects\Project A\
and you tried to load an existing project that is located in this directory:
C:\Projects\Project A\.
This will not work!!! 

How to install Flex Builder Plugin for Eclipse:

For a long time I have been switching back and forth on Adobe's Flex Builder IDE and Eclipse with Flex Builder Plugin.  They have similar interlace and tools, so to me they are basically the same.  However, I have had issues with debugging when using eclipse...

Since each program only allow you to have one workspace and one project opened at a time, I would always have both of these program installed on my computer.  This allows me to have my current project open on one and the other with an old project that I can use for reference or quick search. 

Anyway, below are instructions on how to install Flex Builder Plugin for Eclipse.