Unable to install Crystal reports

Hi

I have uninstalled Crystal reports Basics 2007 and reinstalled as I couldnt get it working on a client PC.

Now when i run the crystal reports exe i get below error messge

(I have Net Framework 3.5 running and also have the Crystal reports 2008 SP 1 running)

error 1904 module c:\program files\business object\businessobject enterprise 12.0\win32_x86\reportconvtool.dll failed to register.

HRESULT - 2147024769.

can someone help me as i need to get this sorted out urgently

many thanks

Apsara