Error: Cairo 1.2.6 does not yet support the requested image format:
Alpha mask: 0x00000000
Red mask: 0x0000003f
Green mask: 0x000007c0
Blue mask: 0x0000f800
Looks like an RGB 655 format to me---retitling to indicate as much in the bug report.
Also reported as debian bug
What graphics hardware is this happening on?
This bug is now fixed in the cairo 1.5.14 snapshot and will appear in the imminent 1.6.0 release.
Please test and let me know how things go.