What is an "open document T" file? Are you using Open Office or something? For illustration lets assume yes for now...
In order to print out a document, windows need to be able to "open" it with an associated application and that app has to understand the "Print" DDE command from windows.
So if that document is, for example, and Open Office document and you don't have Open Office installed then it's not going to print because there is no app associated with it.
If you DO have Open Office installed (again assuming that is the program responsible for the document). Then it may be a case of the app needing to be upgraded to work with Windows 7 properly :/
I have run into this problem even with some older (6 year old) Microsoft software running on Windows 7 unfortuantely. In that case, even double clicking on the file will not open the file. It launches the app, but then the file does not load.