Something that has bitten me a couple of times. If you are trying to copy an STSADM command line from a web page and paste it directly to the command prompt box on a SharePoint server. Don’t.

It doesn’t work because of something to do with pasting HTML style text into a DOS text prompt.

Re-type the command line or paste to a text editor as unformatted text and remove any formatting before copying and pasting from the text editor to the command line.