I installed CellProfiler and CellProfiler Analyst on a Windows 7 computer. The default installation folder for CP was C:\Program Files\ and for CPA it was C:\Program Files (x86), so I used those. When running CPA the image viewer did not work until I manually copied the folder C:\Program Files\CellProfiler\imagej\ into C:\Program Files (x86)\CellProfilerAnalyst.
Petter, what version are you trying to install? The version that is released on cellprofiler.org?