Hmm, not sure. Using 10.3 with 1E9 on a x64 system, no problems here.
Might check after uninstalling flash that nothing's in these folders here -
Windows/SyswWOW64/Macromed
Users/Appdata/Roaming/Macromedia
Not sure if it's an option for you, but might also
reset IE, and try installing it after that.