Cubace 6 randomly closes down

Hi. When using only 4 or 5 midi trcks Cubases 6 closes with the following error message…
eLicence controller error.
Application Cubase 6 has caused the following error.
DCOM connection to program "Sysopos.exe has failed.
Error… The RCP server is unavailable.
Please help
Thanks in advance
Lucia.