VBA API Call returns value when run on one computer but not on another identical one - api

Question

I have an API call that returns a value from a foreign listview (Java application) that works just fine on my computer. When I try to run the same call on my colleague's computer, however, it just returns "0". We work in an office and our computers are identical--same model, same version of Windows, same version of MS Office (with Excel). The file with the API call resides on a shared network location, so it is the exact same file, exact same code that I am running on both machines. I am not very well-versed in API, so I'm probably missing something simple, but I haven't been able to solve it. Can anyone clue me in to why the code works on one machine but not the other?
Here's the code with the call--see my NOTE about halfway down that shows where I get a discrepancy:
Public Function GetListviewItem(ByVal hWindow, pRow) As String
Dim result As Long
Dim myItem As LV_ITEM
Dim pHandle As Long
Dim pStrBufferMemory As Long
Dim pMyItemMemory As Long
Dim strBuffer() As Byte
Dim index As Long
Dim tmpstring As String
Dim strLength As Long
Dim pColumn As Long
Dim lProcID As Long
'**********************
'init the string buffer
'**********************
ReDim strBuffer(MAX_LVMSTRING)
pColumn = 2
'***********************************************************
'open a handle to the process and allocate the string buffer
'***********************************************************
GetWindowThreadProcessId hWindow, lProcID ' Get the process ID in which the ListView is running
If lProcID <> 0 Then
pHandle = OpenProcess(PROCESS_VM_OPERATION Or PROCESS_VM_READ Or PROCESS_VM_WRITE, False, lProcID)
pStrBufferMemory = VirtualAllocEx(pHandle, 0, MAX_LVMSTRING, MEM_COMMIT, PAGE_READWRITE)
'************************************************************************************
'initialize the local LV_ITEM structure
'The myItem.iSubItem member is set to the index of the column that is being retrieved
'************************************************************************************
myItem.mask = LVIF_TEXT
myItem.iItem = pRow
myItem.iSubitem = pColumn
myItem.pszText = pStrBufferMemory
myItem.cchTextMax = MAX_LVMSTRING
'**********************************************************
'write the structure into the remote process's memory space
'**********************************************************
pMyItemMemory = VirtualAllocEx(pHandle, 0, Len(myItem), MEM_COMMIT, PAGE_READWRITE)
result = WriteProcessMemory(pHandle, pMyItemMemory, myItem, Len(myItem), 0)
'*************************************************************
'send the get the item message and write back the memory space
'*************************************************************
'NOTE: THE 'result' VARIABLE IS WHERE I GET VALUES, BUT THE OTHER COMPUTER GETS '0'
result = SendMessage(hWindow, LVM_GETITEMTEXTA, pRow, ByVal pMyItemMemory)
result = ReadProcessMemory(pHandle, pStrBufferMemory, strBuffer(0), MAX_LVMSTRING, 0)
result = ReadProcessMemory(pHandle, pMyItemMemory, myItem, Len(myItem), 0)
'**************************************************
'turn the byte array into a string and send it back
'**************************************************
For index = LBound(strBuffer) To UBound(strBuffer)
If Chr(strBuffer(index)) = vbNullChar Then Exit For
tmpstring = tmpstring & Chr(strBuffer(index))
Next index
tmpstring = Trim(tmpstring)
'***********************************************
'deallocate the memory and close the process handle
'**************************************************
result = VirtualFreeEx(pHandle, pStrBufferMemory, 0, MEM_RELEASE)
result = VirtualFreeEx(pHandle, pMyItemMemory, 0, MEM_RELEASE)
result = CloseHandle(pHandle)
If Len(tmpstring) > 0 Then GetListviewItem = tmpstring
End If
End Function
Thanks to anyone who might have some suggestions.