Opening of *.dat files

Those are generally binary files and really can't be opened by any program other than the app that requires it to run. Occasionally developers will use this extension to store plaintext files (though it's very rare). Try opening the file in Notepad and if it doesng work, your probably outa luck.

Get a hex editor. HxD has a portable version and seems to work well. The streamwriter_data.dat appears to be a binary file as pyromaniac said.

Clair