You need to install personal isogen version 6.3.0 for build 100715, this is availabel to download, type the following line(including space) in internet explorer, unzip the file and extract all files to CAESAR 5.20 folder.
"www.coade.com/uploads/caesar/Personal Isogen 6 SP 3.zip"
Regards,
Shawn Zhong
CADWorx & Analysis Solutions
Intergraph Process, Power, & Marine
12777 Jones Road, Ste. 480, Houston, TX 77070 USA
Shawn.Zhong@intergraph.com