I have been having trouble with IE 8 with our company's main application which runs on oracle forms with jinitiator. After an extensive google search, i was able to find a much needed workaround and a solution.
Workaround - Replace the C:\Program Files\Oracle\JInitiator <version>\bin\hotspot\jvm.dll with Sun's JRE version C:\Program Files\Java\jre <version>\bin\client\jvm.dll (these folder location are the default ones, change it to suite your environment. Make a backup before you replace).
Solution - Oracle forms to use JRE and not jinitiator.