Why does 7-zip.exe return “Access is denied” with these arguments/parameters?

Question

In a batch file:

START "7-zip" /D "C:\Program Files\7-Zip\" "7z.exe" a -o testArchive F:\test

Or, alone on the cmd as:

7z.exe a -o testArc C:users\user\desktop\test

returns "Access is denied". I would expect it to run 7-zip with the specified parameters. Why doesn't it?

Here is the code for the batch file:

@echo off 
:Variables 
set SOURCE=F:\myDocuments\ 
set DESTINATION=E:\myDocuments\ 
:If disc space is available, make tar ball or .7z or whatever of /myDocuments and place it in F:/Backups 
START "7-zip" /D "C:\Program Files\7-Zip\" "7z.exe" a -o <F:> testArchive F:\test 
pause 
:echo %SOURCE% 
:echo %DESTINATION% 
:pause 
:run create sync. on documents to H:/myDocuments 
:Otherwise, say there's not enough disc space

This doesn't happen if proper syntax is followed for the z-zip command. Access is Denied was due to a 7zip syntax error.