How do I install RXTX-2.2pre1.jar on Windows 7?

I am using processing code that gives the error, RXTX Version mismatch Jar version = RXTX-2.1-7 native lib Version = RXTX-2.2pre2

I have followed the instructions on the processing forum as below,

goto and download from "Binary" column. goto C:\Users\Downloads\\rxtx-2.1-7-bins-r2 and copy RXTXcomm to C:\Program Files\processing-1.5.1\java\lib\ext goto C:\Users\Downloads\\rxtx-2.1-7-bins-r2\Windows\i368-mingw32 and copy both rxtxParallel.dll and rxtxSerial.dll to C:\Program Files\processing-1.5.1\java\bin

However I did not have permission to copy RXTXcomm into C:\Program Files\processing-1.5.1\java\lib\ext .

Could anyone help me out? Thank you.