Hello,
I know this post is rather old but perhaps I could help someone else facing this problem.
I managed to solve this problem with these three steps:
1. I changed the symbolic link in /usr/sap/<SID>/SYS/exe: the dbg-link pointed to the wrong directory. It pointed at the exe-directory on our NAS but is has to ponit to the exact kernel-directory on the NAS (/.../exe/uc/linuxx86_64/ in our case).
2. The variables of the <sid>adm-user-enviroment were partually wrong. In the directory /home/<sid>adm/ the files dbenv.sh and ...csh exported the wrong SAP_EXE variables. I just removed the hash key at the line where the wright SAPEXE-var is set und put an hash key at the beginning of the line where the wrong SAPEXE was set.
3. In our case an old (to old) version of sapinst was used to install the application server. This sapinst changed the instantclinet-link at /oracle/client/... to an older version. With this old version of the instantclient the connection to the remote database was not possible. So I just changed the link back to the old instantclient again.
Hope this infomation could help someone.
Joschka