ctypes WindowsError:access violation

[trayres]

Hi all!
I'm trying to use ctypes to access a function in a DLL. Here is the function prototype:
extern "C" void__stdcall__ declspec(dllexp ort) ReturnPulse(dou ble*,double*,do uble*,double*,d ouble*);

Here is the python code. It is really simple: I initialize each of the variables, then make a pointer to them.

Python code:

FROGPCGPMonitorDLL = windll.LoadLibrary('C:\Program Files\MesaPhotonics\VideoFROG 7.0\PCGPMonitor.dll')

#Function argument:double* pulse
sizePULSE = 2 ##Manual is super unclear here
pulse = c_double * sizePULSE
ptrpulse = pulse()

#Function argument:double* tdl
sizeTRACE = FROGPCGPMonitorDLL.GetSize()
if sizeTRACE == 0 :
    sizeTRACE = 1 #Manually set size to 1 for testing purposes
    print "Size of FROG trace is zero. Probably not right."
tdl = c_double*sizeTRACE
ptrtdl = tdl()


#Function argument:double* tdP
sizeTRACE = FROGPCGPMonitorDLL.GetSize()
if sizeTRACE==0:
    sizeTRACE=1
    print "Size of FROG trace is zero. Probably not right."
tdP = c_double*sizeTRACE
ptrtdP = tdP()


#Function Argument:double* fdl
sizeTRACE = FROGPCGPMonitorDLL.GetSize()
if sizeTRACE==0:
    sizeTRACE=1
    print "Size of FROG trace is zero. Probably not right."
fdl = c_double*sizeTRACE
ptrfdl = fdl()

#Function Argument: double* fdP
sizeTRACE = FROGPCGPMonitorDLL.GetSize()
if sizeTRACE==0:
    sizeTRACE=1
    print "Size of FROG trace is zero. Probably not right."
fdP = c_double*sizeTRACE
ptrfdP = fdP()

#Use the function
FROGPCGPMonitorDLL.ReturnPulse(ptrpulse, ptrtdl, ptrtdP,ptrfdl,ptrfdP)

If anyone is interested, the C function is for a DLL to control the Mesa Photonics VideoFROG. The manual is here:

http://www.mesaphotonics.com/assets/applets/VideoFROGv7Manual.pdf

Page 68 (appendix C) and page 69 contain the function prototype and the description of the function. I'm pretty sure GetSize() is working, so that eliminates one potential error point.

The error I get, when I call the function, is:
WindowsError: exception: access violation writing 0x00001001

I'm beginning to come to my wit's end with this problem. Any and all help or guidance of any kind is greatly appreciated!!
Thanks all!