Had this exact same error. Here is the post: http://community.crystalspace3d.org/forum/index.php/topic,1299.0.html
Basically, there is a bug in crystal space code, and a file needs a patch. My post links to that patch.
Or, you can just download the file I'm posting, and place it in $CRYSTAL/plugins/mesh/sprcal3d/object/
A purist might say that this isn't a bug in crystal space, but rather the implementation of cal3d changed. However, I say that since the instructions are to download the latest cal3d, rather than a specifc cal3d, the fact that crystal space aims at a moving target and misses, crystal space still misses it's target. If they didn't want to aim at a moving target, they should have specified which version to download, or offer a working version on this site.
Anyway, replace this file, and it should work. Oh yeah, and it works with cal3d revision 420 (I think 425 too). If you use a newer version, I doubt you'll have any problems, but no gaurantees from me. It is, after all, a moving target.