Documentation
IPS_LibrarayExists
 boolean IPS_LibraryExists (string $LibraryID) 
  Parameters
| LibraryID | ID of the library | 
Returns
If the LibraryID exists in the system, TRUE is returned, otherwise FALSE.
Description
The command checks if the library with ID LibraryID exists.
Example
if (IPS_LibraryExists("{7DC57F9A-C095-4CDE-A6F0-2CB35A29A8FE}")) 
    echo "ELV Library exists!";