As per the last response:

"The login is controlled by the file EZUSRFIL.ld4, which also usually resides in the ...\asp directory. If you want to recreate this file (ie this will delete all users and refresh the info), you can rename it, and when you open an Adagio module, use SYS for both the user name and password, and that should get you in as the System Admin login."

To clarify, either something has happened to the ezusrfil.ld4 file, or you have mistyped the username and/or password to get into Adagio. In any case, rename the file. Note that if you use any Softline (AO) for windows products (ie ContactMaster for Windows for ACCPAC Plus), then you will lose all usernames and passwords for that product's log on as well and they will have to be re-entered after you log on as SYS-SYS after renaming the file.

Regards