Hi. I've already have this problem and I fixed it. Just disable Multi-Threading Processing option In advanced section in Excel 2010 preferences. Maybe sounds weird, but it smeels like driver-compatiblity issue.
(In my case, if I reopen Excel, this option will be enabled again. If this is your case you must install a hotfix from MS: http://support.microsoft.com/kb/2598350)
Good luck everyone, hope it works =)