Have you installed the MS Compatability Pack? If not, try this link. http://www.microsoft.com/en-us/download/details.aspx?id=3
The Compatability Pack is not applicable to this situation. It is for users of older versions of Office (2003, XP, 2000) who want to be able to open files created on later versions (2007, 2010, 2013) versions of Office. Since the two versions of Office involved here are Office 2007 and Office 2010, the Compatability Pack does not apply.
Edit: cwhartley, upon reading lau's 2nd post again, where he mentioned Office 2003, I see why you suggested installing the Compatability Pack but, again, he does not have an earlier version of Office, so it does not fit the situation here.
lau, if you could attach an Excel 2010 file (could be fictitious data) containing a chart to a forum post, I could try opening it in my Excel 2007. This could provide some confirmation of whether this apparent incompatibility is not just an issue with your particular edition of Office 2007.