How I can backup a site collection and restore it to a new site collection? [duplicate]

Question

Possible Duplicate:
Backup and Restore SharePoint 2010 SiteCollections

I have a site collection running on SharePoint Server 2010. What I would like to do:

1. a backup of the existing site collection
2. create a new site collection (on the same or different server)
3. restore backup from step one to site collection step 2

using PowerShell command.

Here is the command I'm using to do a backup and restore:

Backup-SPSite -Identity "http://mysite.com" -Path "D:\backup\mysite.bak"

Restore-SPSite -Identity "http://new_mysite.com" -Path "D:\backup\mysite.bak"

But I'm getting an error that "Your backup is from a different version of Microsoft Sharepoint Foundation and cannot be restored to a server running the current version. the backup file should be restored to a server with version 4.0.145.0 or later

I'm not sure if it's a right approach. What would be the best way to do it?