The .asadmintruststore file is not described in the Application Server documentation. If this file does not exist in the server administrator's home directory, you may experience serious bugs when upgrading certain applications hosted on the server.
If possible, the asadmin start-domain domain1 command should be run by user who installed the server.
If it is not run by that user, the .asadmintruststore should be moved or copied from the home directory of installing user to the home directory of the running user.
Note that if the file is moved (not copied) from the installing user's home directory to the running user's home directory, you might experience application upgrade problems, as described in bugs 6309079, 6310428 and 6312869, because the upgrade/install user (normally root in Java ES) will no longer have the .asadminstruststore file in his or her home directory.