Porting set are the binaries (executable files) that makes the Baan/LN run. These files includes ntbshell.exe (windows) or bshell (Unix), DB Driver files, include files etc.
Solutions are the PMC solutions that are provided by Baan Support to fix any bug or to enhance the functionality. These come as a stand alone solutions or bunch of weekly/monthly solutions as released by baan support. Each soluton has a defined dependancy and system makes sure that all the dependencies are installed before installing the solution. This makes the installation safe while maintaining its sequence of installation
Patches comes in the form of dump with ".dmp" as extension and are installed using the session ttiex1284m000. Both solutions and pathces contains the baan components e.g. forms, scripts, objects, reports etc. The difference between patches and solutions is that there is no mechanism to define the dependancies in a patch and one has to control it manually. There is always a chance of overwriting a newer object with its older version if the correct sequence is not followed. Normally this can be identified by the patch number, but even this is not fool proof.
Hope it clarifies and makes you understand the difference between the three.