You have two options. First, you can buy or borrow an external drive. USB DVD burners selling for $20-40 and might be a handy anyway.
Second, request a card version from your supplier.
In the meantime, you can try trial versions of the latest version which is actually an improvement on the CD-ROM version via
Free SilkPix Developer Pro5 Trial | Silkypix The Trial is good for 30 days.
---------- Post added 12-16-15 at 03:07 PM ----------
The issue of downloading from Ricoh is that it's only an update though. Not the full version.