programs won't compile

I tried to compile my programs today, but got the message below…I’ve been compiling for 5 years and never had a problem…everything worked fine yesterday, but today none of my programs will compile…here is the message I got: (What should I do to fix this?)

Could not write build preferences file
java.io.FileNotFoundException: C:\Users\Owner\AppData\Local\Temp\build7969589882996646881.tmp\Combo_55.cpp (The system cannot find the path specified)
	at java.io.FileOutputStream.open0(Native Method)
	at java.io.FileOutputStream.open(FileOutputStream.java:270)
	at java.io.FileOutputStream.<init>(FileOutputStream.java:213)
	at java.io.FileOutputStream.<init>(FileOutputStream.java:162)
	at processing.app.debug.Compiler.preprocess(Compiler.java:1268)
	at processing.app.debug.Compiler.preprocess(Compiler.java:1228)
	at processing.app.debug.Compiler.compile(Compiler.java:358)
	at processing.app.debug.Compiler.build(Compiler.java:121)
	at processing.app.Sketch.build(Sketch.java:1109)
	at processing.app.Sketch.build(Sketch.java:1084)
	at processing.app.Editor$BuildHandler.run(Editor.java:1955)
	at java.lang.Thread.run(Thread.java:745)
java.lang.NullPointerException
	at processing.app.debug.Compiler.adviseDuplicateLibraries(Compiler.java:477)
	at processing.app.debug.Compiler.build(Compiler.java:128)
	at processing.app.Sketch.build(Sketch.java:1109)
	at processing.app.Sketch.build(Sketch.java:1084)
	at processing.app.Editor$BuildHandler.run(Editor.java:1955)
	at java.lang.Thread.run(Thread.java:745)

(deleted)

Thanks! That worked perfectly! :)