When you use NWDOUT of AutoCAD 2010, and your Navisworks 2010 is a network version, then you will consume both your AutoCAD license and a NavisWorks license until the command is finished. It then will release the NavisWorks license. So, if you have 1 network license of NavisWorks and someone is running the program the person trying to use NWDOUT will receive an error.
Autodesk is aware of this issue and it designed/programmed it to work in this fashion, to workaround this issue use the NWCOUT command as it does not consume a NavisWorks license.
This can also apply to other Autodesk products that have the Navisworks plug-in installed.
If you need any help on this or any other issue call the Avatech National Support Center at 800-808-7645. Remember our contract holders come first and first time callers after that. If you’d like to purchase a support contract we can help with that too.