Yes. Some people, myself included, have had issues with the FOG download manager. Since this appears to be an issue you're having, go here:
http://forum.us.runesofmagic.com/showthread.php?t=66641
The link will provide two lists of direct file downloads, one for the Full client, one for the Slim client. Choose one list to download from. I'd recommend downloading no more than two files at a time, just to keep your download speed at a reasonable rate. Once all the downloads from a list are finished, you can begin the installation by running the ROMSetup.exe file.
Make sure that you've deleted any of the files which the FOG download manager saved before downloading from the direct file links.