PySerial could not open port COM4: [Error 5] Access is denied - please help

[Adam]

"John Nagle" <nagle at animats.com> wrote in message 
news:jse604$1cq$1 at dont-email.me...
> On 6/26/2012 9:12 PM, Adam wrote:
>> Host OS:    Ubuntu 10.04 LTS
>> Guest OS:    Windows XP Pro SP3
>>
>>
>> I am able to open port COM4 with Terminal emulator.
>>
>> So, what can cause PySerial to generate the following error ...
>>
>> C:\Wattcher>python wattcher.py
>> Traceback (most recent call last):
>>    File "wattcher.py", line 56, in <module>
>>      ser.open()
>>    File "C:\Python25\Lib\site-packages\serial\serialwin32.py", line 56, 
>> in
>> open
>>      raise SerialException("could not open port %s: %s" % (self.portstr,
>> ctypes.WinError()))
>> serial.serialutil.SerialException: could not open port COM4: [Error 5]
>> Access is denied.
>
>     Are you trying to access serial ports from a virtual machine?
> Which virtual machine environment?  Xen?  VMware? QEmu?  VirtualBox?
> I wouldn't expect that to work in most of those.
>
>     What is "COM4", anyway?   Few machines today actually have four
> serial ports.  Is some device emulating a serial port?
>
> John Nagle
>

Thanks, and yes, I am using VirtualBox.  My laptop does not have a serial 
port so
I use a USB-to-serial converter, which is assigned COM4.