It is not possible to install Parallels Tools in a SUSE 12.3 virtual machine.
In parallels tools installation log file
/var/log/parallels-tools-install.log inside the VM you can find:
/lib/modules/****/build/include/linux/version.h (No such file or directory)
Support for SUSE 12.3 has been included into PSBM5 Update 9.
Install the latest updates on the server :
~# vzup2date -m batch install --core --tools --self-update --loader-autoconfig