Archiving SharePoint 2010 sites using PowerShell

I am having problem archiving my SharePoint sites.

Our one root site is https://sharepoint.ourcompany.co.uk. Under this we have 20 or so subsites - Job1, Job2, Job3 etc.
I used to run the following command to a folder on an external USB hard drive (G:). Now that folder is on a network share but still (G:). That is all that has changed. I saved this command to a text file because I only archive every 6 months or so and I am sure that only the physical save location has changed, but is still G:

PS C:\Users\admin>  Export-SPWeb -identity https://ourcompanysharepoint.com/Job1 -path G:\SharePoint_Site_Archives\Job1\Job1.cmp


But I get this error in Red

Export-SPWeb : G:\SharePoint_Site_Archives\Job1\Job1.cmp
At line:1 char:14
+  Export-SPWeb <<<<  -identity https://ourcompanysharepoint.com/Job1 -path G:\SharePoint_Site_Archives\Job1\Job1.cmp
    + CategoryInfo          : InvalidData: (Microsoft.Share...CmdletExportWeb:
   SPCmdletExportWeb) [Export-SPWeb], DirectoryNotFoundException
    + FullyQualifiedErrorId : Microsoft.SharePoint.PowerShell.SPCmdletExportWeb

Am I missing something?

Thanks for your time.