If this file does not exist in the server administrator's home directory, you might experience serious bugs when upgrading certain applications hosted on the server.
If possible, have the asadmin start-domain domain1 command run by the user who installed the server.
If the command is not run by that user, the .asadmintruststore should be moved or copied from the home directory of the 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. These problems occur because the upgrade or installation user does not have the .asadminstruststore file in the home directory.