The portlet located at:
requires the privilege "Manage Observations".
However, this privilege is not a part of the 1.6.x core privileges.
I have not checked other OpenMRS versions.
These privileges are required to manage observations in OpenMRS, "view observations", "add observations" and "edit observations".
Change the find obs page to use the appropriate privilege check, wrap the related lines in the jsp inside Openmrs' require tag