AIMMS Knowledge Base Article – KB000012


Could not initialize DLL



You must have an AIMMS license that allows you the use of a solver, and a license for the solver in case you have a ‘link only’ license, before being able to use a solver in AIMMS. 


When you try to add a solver in the solver configuration dialog, the following error message appears:

        Could not initialize DLL libcpx91.dll

Where libcpx91.dll can also be any other solver DLL that is supported by AIMMS.


There are several possible causes for this problem:

  • You have a license to use AIMMS with CPLEX, but the CPLEX solver files (.cpx) are out of maintenance.
  • Your AIMMS license does not allow the use of this solver.
  • you do have an AIMMS license with solver link, but the solver license is not setup correctly.



For the several causes there are different resolutions:

To update your CPLEX solver files, you can contact us at Support@aimms.com. Please, mention your license number(s) for which you need the new files. Note that your license must be in maintenance to update your solver files.

When you want to use a solver that is not yet supported by your AIMMS license, you need to upgrade your AIMMS license with a solver link (in case you already have a license to the solver), or with a solver.

If you have purchased an AIMMS license with ‘link-only’ you are able to use your own solver license in combination with AIMMS. Note, that CONOPT, XA, BARON and LGO cannot be used with link-only. To link the solver, please follow the steps described in how to link a solver to AIMMS.

More information

For more information, please contact us at support@aimms.com.  



Last reviewed: 18-05-2006