Could you please do this and post the results listed in that newly created file?
Please post those results by using Code tags... You can do that easily by being in post "advanced mode," highlighting that file's text, then pressing the "#" icon in the post edit toolbar. that will add the code tags to the beginning and end of that highlighted text.
dpkg --get-selections > installed-software
The way I do this is from a connected desktop, open a terminal session and sh into my server. Then I can cat the file and cut and paste what is in it into my posts or bug reports... of course you could always upload it from the server using a text-based browser (I sometimes do that), but not as easy or as fast...