Sql develoeper Configuration File access denied

I have install Oracle 32 bit DB in Windows 7 (64 bit). When I try to run sqldeveloper, it asked me to enter full path for java.exe . I have set java.exe of 64 bit but it have to be of 32 bit java execution path. When I try to edit configuration file of sqldeveloper to set have 32 bit java execution path, it won't have me to edit that file. I give me pop up box "Access Denied". I have check all the properties for that file and have full control access but its not allowing me to edit file. What is wrong ?