I had to use an ftp program to delete all the stuff created by articles.
My story:
I just tried to install Articles on a fresh install of 2.2.1 and it failed - it seems that Quip was missing see this bug report -
http://tracker.modx.com/issues/7560
I tried to reinstall, removing things, redownloading, download quip separately and so on - but nothing worked.
So I removed everything (with the manager) - but this did not remove everything so...
I used my ftp program to delete everything in the core/components and core/packages directories (well I actually left wayfinder, core and .gitignore alone)
Then:
1 - downloaded Articles 1.5.1 and Quip 2.3.0
2 - installed Articles - it did so without complaint - Quip was not installed
3 - installed Quip
I have not yet tested fully whether everything works, I have set up a blog so looks promising.
One more odd thing - Articles installs getresources 1.4.2 - but if you look for the extra it is called getResources - the system believes them to be the same extra so maybe the capitalization does not matter - however I had an issue with an 2.2.1 upgrade and I know that when I upgraded getresources it spells it getResources 1.4.2 - probably nothing but...