I actually got a reply from MAXON about this, which seems to have worked well - I'm not sure I understand exactly what the solution entails, but if it ain't broke!!
If anyone else has this issue, here is the MAXON solution:
1. Select the CINEMA 4D.exe in the Explorer and press the right mouse button.
2. Create a shortcut for the program.
3. Open the properties of the shortcut.
4. The first editable field of the shortcut contains a line called "Target" which contains the program path and name enclosed in quotation marks. Add one space after the last quotation mark and add g_threadedRedraw=false (without any quotation marks) at the end of this line.
The resulting "Target" line might (depending on the install path) be something like: "C:\Program Files\MAXON\R17\CINEMA 4D.exe" g_threadedRedraw=false
5. Confirm your changes with "OK".
If you still encounter problems using this driver, disable OpenGL to avoid further crashes until a new version of the driver is available
if it is really weight problem you have to adjust the weighting , another thing , check the rotation of the joints , maybe something had been rotated by mistake
also , always do the rig and weight in a separate file , so you can go back and fix it