I think try copying this graph in impress. I haven't been able to reproduce the problem again... When I paste the graph into impress now, it simply doesn't show up.
Untitled 1.ods (application/Calc), 12.91 KB, created by bananaphone103 on 2012-08-14 04:15:18 UTC
Creator: bananaphone103
Created: 2012-08-14 04:15:18 UTC
Size: 12.91 KB

The attachment is not viewable in your browser due to security restrictions enabled by your Apache OpenOffice (AOO) Bugzilla administrator.

In order to view the attachment, you first have to download it.

Actions: View
Attachments on issue 120559: 78927 | 80015 | 80801 | 81039