Just a note for exporting PDFs, try Googling CutePDF. When you install that, you click "Print" and select CutePDF as your printer to export what you're working on to a PDF file.
I liked your piece, thoughI don't have much to say about it. There are some places that are really empty-sounding, such as m.19, where I think the oboe could come in sooner, and m.21, where it feels like the oboe dropped out sort of abruptly. Also, are you intending to have more than one player on each part? If not, I would delete the C-sharp in the flute part in the last measure.
Also, regarding the first measure and m.11, you could write the flute part with a dotted half note with a mordent instead of the way you have it written now. This looks cleaner, and it produces the same effect you were trying to get.