Here's the instructions again to provide some context:
following in nsFilePicker.js which is located in the app's components
directory. After making the change you have to re-register the
components which is easily accomplished by disabling then re-enabling
an extension and then restarting. Installing or un-installing an
extension will also force a component registration.
**** change:
compMgr.registerFactoryLocation(FILEPICKER_CID,
"FilePicker JS Component",
//@line 278 *snip*
"",
//@line 280 *snip*
fileSpec,
location,
type);
**** to:
Code:
compMgr.registerFactoryLocation(FILEPICKER_CID,
"FilePicker JS Component",
//@line 278 *snip*
FILEPICKER_CONTRACTID,
//@line 280 *snip*
fileSpec,
location,
type);