Hi Elena, You can also remove the teachpack from column one. It is, however, simple enough for students to only add the teachpack in column 2. Once you add a teachpack, it remains added until it is removed. My first year students run DrRacket without removing the teachpack all semester. Marco <div class="gmail_quote">On Sep 6, 2013 10:42 PM, "Elena Machkasova" <<a href="mailto:elenam@morris.umn.edu">elenam@morris.umn.edu</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Good evening, this may've come up before, but I looked through the last few messages and did a bit of searching, and couldn't find anything about this problem. My apologies if this is already a known issue. When DrRacket is installed, it comes with 3 pre-installed teachpacks, including image.rkt. However, image functions (rotate, square, etc) are undefined. Installing the teachpack from the middle column in the "add teachpack" list fixes the issue. However, if the user then tries to add the teachpack and happens to click on it in the first column, they get an error message "module: identifier already imported from a different source". The solution that seems to work then is to clear both teachpacks and then install the one in the middle column. This behavior takes place for both Racket 5.3.4 and 5.3.6, for Windows and Linux (Fedora 18). I don't know if it's happening on a Mac as well. If there is a plan to fix it in the next release, could you let me know? We might wait a couple of weeks to upgrade our lab to 5.3.6 is we can get an upgrade with this issue fixed. Many thanks! Elena University of Minnesota, Morris ____________________ Racket Users list: <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> </blockquote></div>