If you receive an error message on your client installation when trying to check a license out of your ExtendSim 9 network license it is probably the result of not having sufficient permissions on your client machine to checkout the license. The checkout process requires some administrative rights on the client machine and many companies are restricting these rights from users.
Try using the right-click command Run as administrator. If this doesn't work, then you may not have been granted sufficient permissions by your company on the machine to check out a license.