Check your webserver and php logs. I've curious as to what the error is. The error was on the admin panel dashboard? Or was it when you went to another tab?
I've just spent a little time pouring through some of the installation code. (/install) and found that the salt only appears to be used in a couple places.
install.php line 148:
$configfile= str_replace('%CONFIG-SIRI',Misc:(32),$configfile);
Where it makes the salt and puts it into the config file.
/set/upgrade.php line 88-94:
$sql='UPDATE '.EMAIL_TABLE.' SET updated=NOW(), mail_protocol="POP",mail_encryption="NONE",mail_port=110,mail_active=0 '.
',mail_host='.db_input($row).
',mail_fetchfreq='.db_input($row).
',mail_delete='.db_input($row).
',userid='.db_input($row).
',userpass='.db_input($row?Misc:($row,SECRET_SALT):'').
' WHERE email_id='.db_input($row);
I propose that if you were to write a quick and dirty routine to update the email table, userpass field using the secret salt from the config file that it may fix your problem. I hope that you don't have a lot of emails in that table. If you wanted to back up that table... and then delete it. You may be able to just reconfigure the email addresses instead.
Anyone else have any ideas?