As an alternate to the utility, you can also open SQL Server Management Studio on your DB Server and change it directly in the dbo.User table.
- Connect to your database and navigate to Databases>ProcessManager>dbo.user.
- Right-click on the object and select Edit top 200 rows.
- In the row for your admin user, you could add a new value in the Password column.
After you change the password, you could then log into the Process Manager and then change it so it is not in clear text in the DB.
I understand that this is a few extra steps, but it should only be used as an alternate to the ChangeAdminPassword.exe utility.