1st problem: when I enter virtuemart configuration I get a message: Error
vmError: Warning, the Safe Path is not accessible (does not exist or no permission), for safety reasons it is very important to create a folder in a path not accessible by an URL or unguessable name,.....

2nd problem: when try to edit shop information (under section "shop") I get error message:
vmError: Save failed with the following error: Username in use.