Since it may relate to installation, I post it for any resolution.
before I remove my older version of TrueView, I installed TrueView 2013-32bit on an XP with all .Net 4 and it worked fine the first time I opened. The next day I open TrueView 2013 it has the following message:
Unable to run DWG TrueView. This may be due to one of the following:
1) This version of DWG Trueview was not installed properly. In this case, you may wish to reinstall DWG TrueView.
2) You do not have sufficient rights to run DWG TrueView.
Wherever I open a DWG files, it gives me the following message: