Hi Manjul,
We have many clients using Adagio modules on NT workstations and/or NT servers and are running without a problem.
Currently, Adagio Receivables, Invoices, and Checks are all 16-bit applications, and Ledger and Payables are 32-bit applications. If you encounter a message such as 'Cannot run 16-bit application', the issue is likely related to something contained in the config.nt, autoexec.nt, or autoexec.bat files.
There are a few topics on the Microsoft Knowledge Base that may shed some more light on this. The one we are aware of are article #s Q103656, Q103014, and Q125905, and there may be other relevant ones. They are too big to include here.
The version of Ledger you stated was for the initial release of Adagio. There have been ptf releases for every module, including a specific one regarding Invoices and NT.