[wix-users] Independent Directory element

[Ven H]

Can't I define an independent Directory element inside a separate fragment
or component? If I do that, I get an error saying "The directory with the
Id 'TestDir' is not a valid root directory. There may only be a single root
directory per product or module and it's Id attribute value must be
TARGETDIR and it's Name attribute value must be SourceDir. " Sorry for
asking such a silly question, but I am new to WiX, so, please forgive me. I
am a newbie and a learner and could use all the help. Hence, please help.

Regards,
Venkatesh