This can becaused by the difference in environment variables for each user. Since licensing operates off of the XILINXD_LICENSE_FILE variable, having this set for the Admin does not mean it is set for another user. In order to resolve this, the student user has to set this environment variable manually.
In the situation where this needs to be done to multiple computers/users, an option would be to edit the settings32/64.bat scripts in the install ISE_DS directory to include the following command:
Where the location is swapped for the location of the license file. It is recommended to also edit the (hidden) scripts located in the ISE, PlanAhead, common, EDK, and SysGen folders with the same command.
Once these are changed, you can then copy them to the installs of all the computers/users.