Symptom
You have for example imported a Support Package or another ABAP change. Now dump LOAD_PROGRAM_CLASS_MISMATCH or LOAD_PROGRAM_INTF_MISMATCH or RUNT_ILLEGAL_SWITCH occurs (displayed in Transaction ST22).
Other terms
LOAD_CLASS_VERSION_MISMATCH, LOAD_INTF_VERSION_MISMATCH
RUNT_ILLEGAL_SWITCH Reason and Prerequisites
Origin of inconsistency:
Read Note 352480. This kernel patch corrects a major cause for such inconsistencies.
In addition, transports or changes in productive operation can cause these inconsistencies. (Notes 0162166, 0162991, 0356208).
In addition, an error during update of the object list in SE80 leads to missing includes in Table D010INC. Since Table D010INC is used as cross-reference, inconsistencies occur when changing includes affected (-> Note 535969).
Correction and description of inconsistency:
During a transaction or a report, program B is called by program A. (CALL FUNCTION, CALL METHOD ....)
The dump occurs if the system finds out at program runtime that program A uses a different version of class C than program B.
If this inconsistency exists, this is mostly because a transport which changed class C was imported into the running system.
Program A then has processed the new version of class C, but program B is still running with the old version.
Analysis:
1. In the dump long text you will find the section "Error analysis":
For example:
The section "PUBLIC" of the interface of class "CL_RSO_REPOSITORY" was changed at program runtime so that inconsistencies were created at runtime.
Program "CL_RSO_RENDER_HTML_LIST_TYPE==CP" uses the interface version 20000920150545.
Program "CL_RSO_REPOSITORY=============CP" uses the interface version 20001003135348.
That means: Program "CL_RSO_RENDER_HTML_LIST_TYPE==CP" uses the interface version: 20.09.2000 / 15:05:45.
Program "CL_RSO_REPOSITORY=============CP", on the other hand, uses the more current version: 03.10.2000 / 13:53:48.
2. Check in ST22 whether the dump only occurs on one server. Solution
Ad (1)
You must at least generate the program with the outdated interface version.
In the present case you must regenerate:
"CL_RSO_RENDER_HTML_LIST_TYPE==CP"
so that it also uses the newest version of the interface of class "CL_RSO_REPOSITORY".
To be on the safe side, you should also generate the second program as well.
In the present case:
CL_RSO_REPOSITORY=============CP.
Ad (2)
If only one server is affected, then it is most likely that the program version on the database is correct but that the version in the program buffer of the server in question is outdated. In this case, generate the program in question on this server. If there are several programs to be generated, you can also restart the server to empty the buffer. If several servers are "affected" according to St22, then generate the program on any server. If the problem is not solvedafterwards, start all application servers to delete the buffers. Thanks, Abhijit | 
Bluesky