Whenever LibreOffice Writer is launched, it also opens a command prompt window that displays the actions being executed within the program.
Known Problem "Bug 42914 - Terminal (command) window is opened when launching any executable". Fixed in Beta1 and Master.
Please do not submit Bug reports concerning 3.5 Beta0. Some bad luck, that version "3.5 Beta0" was terrible buggy. I believe it's not useful to do tests with tat version, please wait for Beta1 (just uploading to mirrors) ad do your tests with that version (or with Master from <http://dev-builds.libreoffice.org/>, of course).
Tests with Beta0 are wasted time.
@Mike Van Wormer II:
Thank you for your attention, please excuse that we did not remove download information timely
*** This bug has been marked as a duplicate of bug 42914 ***