I had the same problem with my new laptop with an NVidia video driver, and just applied the registry fix in the link above. It works now!
The issue is with Mathcad Unimath Font, which is an OpenType font not working correctly with NVidia cards and some ATI cards. Here's the information:
From
http://www.thomasphinney.com/2008/12/no-font-instal/ :
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# The latest problem occurs even with brand new and unmodified machines running Windows XP or possibly Vista, being unable to use Type 1 or OpenType CFF fonts, with an error message that the fonts are �invalid.� It is a video driver configuration issue, and reverting to an older (!) video driver generally solves the problem, but that�s not ideal. A few weeks ago, this problem was solved: it can be fixed with a simply registry edit. Nvidia says the problem occurs on Windows XP only, and Vista users are unaffected, but at least one Vista user has reported they had this problem and the fix resolved it. It affects multiple NVidia cards, and some (unspecified) ATI cards. The fix, posted by David Ingraham in a horribly lengthy thread on the Adobe User Forums, and in a post by �PixelNinja� on the NVidia forums is this:� start of email from HP �Good news.
Nvidia has identified the problem and provided a fix. The way it was explained to me, Windows expects the device driver to be a certain size (maximum). In this case, the nvidia driver is slightly larger than expected. A simply registry entry will resolve the issue in WinXP (the issue doesn�t occur in Vista).
To resolve the problem, do the following: [in Start/Run]
1. Open the registry editor (regedit)
2. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management
3. Add a new REG_DWORD entry called SessionImageSize with a value (decimal) of 20 [Use modify to set the value]
4. Reboot
The Type 1 fonts should now open/install without any problems.
Mona