Why is xcopy returning “invalid number of parameters”?

1.The usual solution for this is to be sure that your filenames are enclosed in quotes, as this can be an issue with batch files where you have something like xcopy %1 %2 and you really need xcopy "%1" "%2".
2.xcopy is parsing the forward slashes in the path to its own binary. You can also run into this if you have your PATH defined using forward slashes instead of backslashes.

reference : http://superuser.com/questions/114178/why-is-xcopy-returning-invalid-number-of-parameters