SoftwareSerial causes error in library

Thank you so much, that gave no errors on start up.

Out of interest though why is it that this is required, I'm used to programming in java and have never come across this syntax before.

However when I tried to use my library I get this error.

hardware\libraries\Motor/Motor.h:5:28: error: SoftwareSerial.h: No such file or directory

This seems strange as SoftwareSerial does exist and is working in other sketches.