The characters in an equation are not printed when you print a Word 2007 document on a Windows XP-based or Windows Server 2003-based computer

To work around this issue, install the Complex Script support files. To do this, follow these steps:

1. Click Start, and then click Run
2. Type intl.cpl, and then click OK.
3. Click the Languages tab.
4. Under Supplemental language support, click to select the Install files for complex script and right-to-left languages (including Thai) check box.
5. When you receive the following message, click OK to close the message:
   You chose to install the Arabic, Armenian, Georgian, Hebrew, Indic, Thai and Vietnamese language files. This will require 10 MB or more of available disk space. The files will be installed after you click OK or Apply on the Regional and Language Options dialog box.
6. Click OK to close the Regional and Language Options dialog box

http://support.microsoft.com/kb/960985