1. There is a slight correction that is due in the LiveCycle documentation. PDF Generator does not require you to use the exact same user for installing LiveCycle, as was used for MS Office installation. It is very much possible to install MS Office with a user U1, and install LiveCycle with another user U2. However, what you still need to ensure is that:
1 (a) User U2 (used to install LiveCycle) has administrative privileges on the system. This condition needs to be met irrespective of whether U2 is a local (machine-specific) user or a domain user.
1 (b) You must manually launch MS Office and Acrobat as user U2 once before running LiveCycle installation. This is required so that you can dismiss any first time dialogs (such as registration and customer improvement program which interfere with the normal working of these applications) once and for all (aka "Never remind me again")
2. By any chance, does the account password contain two consecutive $ characters (like in P@$$w0rd for example)? I think this is a known bug in LC installer. To circumvent this problem, please choose a new temporary password for the user account, install LC, then reset the account password back. You'll also need to manually switch the password for the "JBoss for Adobe LiveCycle ES" Windows service. If this is not the case with your error, please report this to customer support. All user accounts of the form "domain\username" or "username" are supposed to work -- we test this regularly.
3. The password is used only when the "JBoss for Adobe LiveCycle ES" service is restarted. If this service is running all the while, you can change the Windows account password as many times as you want without reconfiguring the "JBoss for Adobe LiveCycle ES" service password.
4. There is a long answer and a short answer for this. The short answer is that LiveCycle PDF Generator has a bit of native code (that runs outside the application server instance) which needs to invoke certain Win32 APIs that fail to work if the calling user does not have administrative permissions. No other component in LiveCycle (with the exception of PDF Generator) has the requirement for administrative privileges.
Adobe LiveCycle ES