Invalid file url

Hello,
There are two options with CSV file.

a) Remote Server URL ( Dynamic CSV )
b) Upload from Computer

If you upload from Local computer, the data is saved in vChart database tables and would remain there. And if you give a Remote server URL, it always fetched the data from this file, doesn't save in database.

I choose a file from local computer and see the data show up but when I save or preview the data disappears from the page. when I reopen the chart I get the message please choose valid file url. Question - is vCharts loading the data for storage somewhere inside joomla database or its own folders or is it always trying to access the file? because the latter is what it looks like. the file is of course originating from a different machine than the joomla installation.