I suspect these axions and WIMPs and other "preposterons" might be a wild goose chase. Electromagnetic forces, a la the "Electric Universe", and/or misconceptions about the nature of space and its interaction with matter might hold the answer to the apparent mass/gravitational anomalies for which Dark Matter theories have been advanced to explain.

And there is another, much more mundane possible explanation, namely large numbers of "rogue planets" or "nomad planets" drifting in the vast distances between the stars. These are very hard to spot astronomically, thus "dark", and they certainly are matter. One estimate has suggested there might be as many as 100,000 of these per star within galaxies, certainly enough to exert sufficient gravitational effects to fill the role of Dark Matter. See my earlier post on the subject, with two links:

http://www.rumormillnews.com/cgi-bin/archive2.cgi/read/45471