This is a known issue. This issue is fixed on software version 5.2.0.3. Upgrading your 3D System to latest software version will fix this issue.
Note: Once the 5.2.0.3 patch is installed, you may still receive the RUA Deserialize error if the Defense Center contains older unified files prior to the 5.2.0.3 patch. Contact Technical Support for assistance in removing the older unified files.