It sounds like you may be experiencing a couple of problems. Before proceeding you should clear you your configuration folder and clear the installed extensions. There is a good set of instructions on this post here:
Once you have done that try installing the extensions again one at a time, if you are prompted to overwrite any existing files select 'yes to all'.
After each install you should attempt to open DW and activate the newly installed product. Then before you install the next one you should clear out the cache.dat file from your system and check that the previous extension is still functioning properly, then proceed to install the next one. Here is a link to a troubleshooting page with instructions on clearing out this dat file:
You will notice that the troubleshooting techniques are listed in opposite order on this page, that is ok, you should clear out your configuration folder first. Please let us know how this goes for you.