Just follow the instructions from their website - http://stardictformaemo.googlepages.com/
"# Put the dictionary files into one of the following directories:

* /media/mmc1/stardict/dic
* /media/mmc2/stardict/dic (N800 only)
* /usr/share/stardict/dic
* ~/.stardict/dic "

So you are not tied to one place to put your dictionaries. I put it on my 16Gb internal SD card so it even does not bother me with my ~40Mb dictionary folder.