There is a known issue where if you try to launch Reports Builder 11g in Windows 7 (32-bit or 64-bit), the Reports Builder will not launch. However, the icon for it appears in the Windows taskbar. Opening it presents the error:
“REP-50125: rwbuilder.conf:java.lang.NullPointerException”
To fix the problem, follow these steps:
1. Go to C:\Oracle\Middleware\asinst_1\config\FRComponent\frcommon\tools\admin
2. Make a backup of cauprefs.ora
3. Look for these entries:
Reports.root_x = “#####”
Reports.root_y = “#####”
4. Replace the numbers (represented by #####) with 0 so that they look like this:
Reports.root_x = 0
Reports.root_y = 0
5. Save and close the file
6. Launch Reports Builder. Reports Builder should work successfully.
NOTE: If you open up Reports Builder at a later date and the problem reoccurs, open up cauprefs.ora and modify the same parameters again with the following:
Reports.root_x = 80
Reports.root_y = 30
Reports.root_y = 76
After applying the settings above, Reports Builder should open successfully.
Source: Oracle Support note 1478627.1