namespace (user defined) not seen by intellisense nor compiler (VB)

Question

• ERROR:
  Namespace or type specified in the Imports 'Project.nsDB2' doesn't contain any public member or cannot be found.
• Make sure the namespace or the type is defined and contains at least one public member.
• Make sure the imported element name doesn't use any aliases.

I create a namespace in a DB.vb file, in the App_code folder
   Imports SQLClient....
      Namspace nsDB
         Partial Public Class clsDB
         ... many public methods... (functions and subs)
         ...

I am able to Import nsDB in a FORM.vb class, no problem
I access the methods in the clsDB at will.

I create a 2nd namespace: DB2.vb, nsDB2, clsDB2, ...methods2...

This 2nd namespace does not appear in the intellisense, nor is seen by the compiler
The build fails with error stated above.

I had thought at some point that, closing down Visual Studio was effective... but it has not worked on this instance.

Can someone help me?
.
Thank you so much,
NicMartel
.