Can't upload on Arduino Uno (Windows 7 64bit)

Hello guys, i need your help please!

I restart working with my arduino this morning, and everything went well until now.
This morning I reinstall arduino 1.0.5 and the driver on my laptop. I was able to upload my sketch and every thing, until i get this error, after trying a sketch that was testing a servo motor.

Binary sketch size: 1,084 bytes (of a 32,256 byte maximum)
java.io.IOException: Cannot run program “C:\Program Files (x86)\Arduino\hardware/tools/avr/bin/avrdude”: CreateProcess error=5, Accès refusé
at java.lang.ProcessBuilder.start(ProcessBuilder.java:459)
at java.lang.Runtime.exec(Runtime.java:593)
at java.lang.Runtime.exec(Runtime.java:466)
at processing.app.debug.Uploader.executeUploadCommand(Uploader.java:125)
at processing.app.debug.AvrdudeUploader.avrdude(AvrdudeUploader.java:333)
at processing.app.debug.AvrdudeUploader.uploadViaBootloader(AvrdudeUploader.java:178)
at processing.app.debug.AvrdudeUploader.uploadUsingPreferences(AvrdudeUploader.java:67)
at processing.app.Sketch.upload(Sketch.java:1671)
at processing.app.Sketch.exportApplet(Sketch.java:1627)
at processing.app.Sketch.exportApplet(Sketch.java:1599)
at processing.app.Editor$DefaultExportHandler.run(Editor.java:2380)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.io.IOException: CreateProcess error=5, Accès refusé
at java.lang.ProcessImpl.create(Native Method)
at java.lang.ProcessImpl.(ProcessImpl.java:81)
at java.lang.ProcessImpl.start(ProcessImpl.java:30)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:452)
… 11 more

The compiling is working, it seems that the communication between my computer and my arduino uno is not.
I tried to reinstall arduino on my computer (several times and version in fact, 1.0.3, 1.0.4 and 1.0.5) and I also tried to reinstal java, but nothing worked.
I did the Loop-Back Test (http://forum.arduino.cc/index.php?topic=73748.0) but it failed to echoe back.
I don’t know what to do, I check the Troubleshoot guide and I tried every step under uploading problem, but it didn’t worked either.

I would very appreciate your help! Thanks

Oh yeah and i was testing with blink sketch on windows 7 64bit

• Close the Arduino IDE

• Start Task Manager

• Sort the list alphabetically

• Is avrdude in the list?

• Close Task Manager

no its not, is it supposed to be?

No. Not under those circumstances.

It looks like there are two unrelated problems. Let's focus on the more serious one...

I did the Loop-Back Test (http://forum.arduino.cc/index.php?topic=73748.0) but it failed to echoe back.

Ensure the only thing connected to the Uno is a USB cable. Does the computer recognize the Uno? Does the computer make the "device insertion" sound when you connect the Uno? Does the Uno show up in Device Manager?

Yes it does all that! Plus I think I found a solution to my problem. I desactivated the windows UAC, restarted my computer and retried to upload a sketch and it work. After, I reactivated it and restarted again and everything still works. So I assumed that the UAC was blocking some operation needed for the setup of the arduino IDE or something like that, so now everything is working fine I think! Thanks

Thank you for the follow-up.

That is bizarre.

I'm glad to know you have it working.