Installing Symantec Directory and/or Symantec Directory Manager may result in DXgroupadd error as shown in example below:
Checking for existing dsa account...
Enter a GID for etrdir, or leave blank to accept the system default 
groupadd: group 'etrdir' already exists
DXgroupadd failed to add group etrdir. Please check.
Release : 14.1
Component : CA Directory
The problem is permissions realted. If you look at the top portion of your install log, you will notice something such as:
or one of its parent directories is not readable/executable
Check the permissions on each of those folders to make sure they are all set to at least 771 (or 775). If one of them is set to 770 (meaning no permissions to 'others'), you will see this DXgroupadd error.
e.g. In the above test case, permissions on 'cadirinstaller' folder was set to 770 while on 'cadirsp3' folder was set to 775. Setting 'cadirinstaller' folder's permissions to 771 resolved the problem.
Once the permissions are adjusted, install should be successful.