struct.pack has become picky about h (short) and H (unsigned short).
diff --git a/Mac/Lib/PixMapWrapper.py b/Mac/Lib/PixMapWrapper.py
index 39e5f8e..72a64ba 100644
--- a/Mac/Lib/PixMapWrapper.py
+++ b/Mac/Lib/PixMapWrapper.py
@@ -15,7 +15,7 @@
# PixMap data structure element format (as used with struct)
_pmElemFormat = {
'baseAddr':'l', # address of pixel data
- 'rowBytes':'h', # bytes per row, plus 0x8000
+ 'rowBytes':'H', # bytes per row, plus 0x8000
'bounds':'hhhh', # coordinates imposed over pixel data
'top':'h',
'left':'h',