the problem is that after some change in the ldcon.so.conf and envirormental variables
I guess you mean /etc/ld.so.conf
Regarding the env. variables (PATH, LD_LIBRARY_PATH, PKG_CONFIG_PATH...), if you have added them in user's ~/.profile, or ~/.bashrc, they are not available for other users. You can add them in /etc/profile if you want everyone to use them.