As Jamie mentioned, check using t-code: /n/IWFND/MAINT_SERVICE
If that doesn't work, maybe you are running an old version of the SAP NW GW, or you are lacking some gw components.
Could you please paste the list of the system components version.
In that case, I need to know if you have isntalled the following:
- SAP_BASIS
- IW_FND
- IW_BEP
- GW_CORE
BR,
Emanuel