Using Windows, if saving a new MIB to the database fails, you typically get an error popup stating "java.io.FileNotFoundException .... (Access is denied)".

This is because the MIB database (MIBS.INI file) is located in the install directory, typically C:\Program Files\...

If you are a regular user (non-administrator), you don't have write access to that directory, hence the "Access is denied" error.

Two solutions:

1. Run the program as an administrator. Right-click the desktop shortcut, and select "Run as administrator"
   
2. Install the program in a non-default location where you have write access as a user (e.g. D:\)

Note that this issue also holds true for saving config files into system directories.