Problem:

We are receiving the message API already in use error when starting the Rumba UNIX display client. (this applies to all the different host types, not just UNIX) The error appears as a message box and clicking OK clears the message and the software starts. How is this resolved?

Resolution:

Check what is set under Options > API Options > Identification/Configuration/Rename DLLs. You will see that it is not set to the default <None> but to a letter somehow. This error actually stems from the fact that all session short names on the desktop must be unique.  

As noted in the help text "To use HLLAPI or DDE":

This topic tells you how to configure your RUMBA display session for use with a HLLAPI or DDE application.

From the Options menu, choose API.

Specify whether you want to use this session with HLLAPI or DDE.

To use EHLLAPI or WinHLLAPI

Select a Session Short Name. This can be any letter of the alphabet (A-Z). When using HLLAPI to communicate with multiple RUMBA display sessions, you must identify each session with a unique HLLAPI short name.