This user's issue was dealt with at the time by Graitec Support. However, for other readers of the question here is a summary of the answers.
1:- The error suggested that the licence had already been returned by the computer and therefore the user was able to re-activate the licence succesffuly at home.
2:- There is a known issue where one part of the drawing style configuration conflicts with gratings. the steps to cure this are as follows:-
Cannot Create Drawings of Gratings
If you are getting problems when you try to create a drawing of a grating from one of the drawing processes please follow the instructions below to fix this.
A) Open “Drawing Process Manager” from the “Numbering and Drawing” toolbar
B) Select the process you need to use, from the “User” folder and click the properties button for the Detail Style Map (the one with a picture of a hammer)
C) In this dialog, go to the Model Object : Mp – Plate. This is the model object used to detail the grating (it uses the style : Mainpart – Plate 1:10CX, which is a style configured to show gratings in MP drawing.). On the left side of the Model Objects column, there is a small button with three dots, which accesses the “Script” dialog. Click on it, and delete all text located in this dialog.
Then change the Mp – Plate model object to Mp – Grating (this MP – Grating model object is located in the “Main Part” category).
D) Click the “Apply” button and then OK.
E) Back in the Drawing Process Manager dialog box click “Apply” then click “Use”. The drawing should then be created. Note that if you are choosing a drawing process that requires you to select the parts to draw you need to select these parts before opening the Process Manager.