In readme file be informed:

INSTALL:

- set XOOPS_TRUST_PATH into mainfile.php
- copy xoops_trus_path/libs/ in the archive into XOOPS_TRUST_PATH/
- copy html/modules/altsys in the archive into XOOPS_ROOT_PATH/modules/
- install it

Please, add this:

INSTALL:

- set XOOPS_TRUST_PATH into mainfile.php
- copy xoops_trus_path/libs/ in the archive into XOOPS_TRUST_PATH/
- copy html/modules/altsys in the archive into XOOPS_ROOT_PATH/modules/
-replace /xoops_trust_path/libs/altsys/include/altsys_functions.php with the file altsys_functions.php in directory Extra in Xoops 2.3.x.
- install it

For this great module works, it is necessary that this file is in the EXTRAS of XOOPS 2.3.x.

This information should appear in that direction README.

It is commonplace for developers, but not for beginners

Thaks