When I open the Datamapper Builder it gives an error: Datamapper Builder can't run with out datamapper enviornment.

In order to run Datamapper Builder, path of Datamapper client must be set using ND_HOME variable.
It could be verified and corrected using following instruction:

1. Open Sysman
2. Go to menu and select help
3. Select details
4. Go to system information tab
5. Check for "ND_HOME=path to installed datamapper client folder ". If you do not find this then set the environment variable as "ND_HOME=path to installed datamapper client folder "
6. Restart the service of XIB.
7. Confirm "ND_HOME=path to installed datamapper client folder "is present in system information tab.

Now, open Datamapper Builder it should open correctly.