This is an odd problem that I came accross when deploying a new Web Part solution to my training server through the command line. After pasting the command that I had copied from the web I received "Command Line Error". The solution is to write the command without pasting it!
A too easy to be true solution...but I assure you it works. The logic behind this is that when copying from one source to another you lose the true encoding in the pasted text and so (The hyphen in particular) doesnt get read by the command line.
The explanation originates from the blog in the related links.