I setup a quick test of the 1.9 sample applications on a Windows 7 - 64 bit environment and was able to narrow down the issue a bit.
When I first ran the 'Image Layer' sample it complained of a 'File Not Found' exception. The issue was that I did not have the 'system32 dlls' that the 1.9 version requires in my SysWow64 folder. The MergeModule we provide with the 1.9 Desktop Edition should allow you to install the necessary dlls in the appropriate SysWOW64 folder on your 64-bit machines, but if you want to do a quick test you can simply copy these dlls from your development system to your Windows 7- 64-bit system.
Here are the dlls I copied from the Windows XP -- 32-bit -- System32 folder to the Windows 7 -- 64-bit -- SysWOW64 folder:
iti_dsdk_dll.dll
MapSuiteECW.dll
MapSuiteGeoRaster.dll
MapSuiteMrSids.dll
MapSuiteMrSids2.dll
NCScnet.dll
NCSEcw.dll
NCSEcwC.dll
NCSUtil.dll
All of the these dlls are provided by the MergeModule as well.
I was able to get both the TIFF and MrSid images in the 'Image Layer' sample application to work with those dlls in place but the ECW image still seems to have some issues: