My issue may be different from vlvrd...
1. I open the IDE under ~\Documents\arduino-1.5.3\
2. I open the example file located at ~\Documents\arduino-1.5.3\libraries\SoftwareSerial\examples\SoftwareSerialExample
3. I hit verify and the pre-processor returns:
SoftwareSerialExample.ino:28:28: fatal error: SoftwareSerial.h: No such file or directory
compilation terminated.
It may be worth noting that I also have ~\Documents\Arduino with the official Arduino IDE since I am still obviously doing AVR development and I don't appear to be able to do this from the Intel branded version.
Thanks,
Byron