It appears that Mike Hann has had this problem regarding the latest AC10 build. Admittedly, my office has recently had a similar problem (also after upgrading to the 1183 build. Arg.), but we discovered the problem arose from importing a TIFF or JPEG file into AC10 and then rotating the image there, in AC10. I.e., the image was scanned sideways and then rotated after being inserted into a layout in ArchiCAD. We "solved" the issue by rotating the images BEFORE inserting them into AC10.
However, after reading the post linked by Laura, it seems that this is not the whole picture....
Good luck!
Zolli