Tanir - did you rename the downloads to "Webster1913[1].zip.001" & "Webster1913[1].zip.002" before uncompressing them?
That worked fine for me, I was left with one file - Webster1913.prc, which I loaded to my SD card.
It's the only dictionary on my CyBook (I'd deleted the sample dictionary it came with) - and works very well.
I looked up the word 'composite' and the initial display listed 'composite' several times and asked me which one I wanted; which doesn't seem very helpful (although it does alert you that there are several entries - don't just settle for the first). When I selected the first, it took to me to the Dictionary and I was then able to page forward through the different definitions, before using the Back button to return to the original text.
Although the lookup highlighter will include surrounding punctuation, the Lookup just ignores that to locate the word.
The only issue I came across was that plural forms don't seem to return any hits ( I tried 'upgrades', 'replacements', 'designers'). I don't know if this is the case for all Dictionaries.
This is an excellent addition to my CyBook library -
jbenny!