Reckon Infrastructure Compatibility Check does not work on Windows Server 2003 and 2008
Legacy KB ID: 4106
Why can’t I access QuickBooks Hosted 2011/12 from my Windows Server 2003?
You cannot access QuickBooks Hosted 2011/12 from a Windows Server 2003 on a Standard Account.
Microsoft has not issued an update for Windows Server 2003 that will allow it to remote access Server 2008 R2 across the internet, as they have done for Windows XP.
Upgrade to QuickBooks Hosted Premium Account.
The Quickbooks Hosted Premium Account utilizes Citrix technology that is compatible with Windows Server 2003 and will enable it to connect to Windows Server 2008 R2.
Premium Account has other benefits such as access from other platforms (Mac, iPads , iPhone and Android) and some improved service for Windows users.