Are you planning a new RT version for Vista 32 bit?
The current version RawTherapee_5.5_WinVista_32 does not work on my computer running Windows Vista Home 32 bit SP1- *.
My the last working version on RawTherapee is 5.0-r1-gtk2_WinXP_32.
After a simple diagnosis RT 5.5, I found that the problem is related to three dll libraries:
- libgmodule-2.0-0.dll - 
- libpangoft2-1.0-0.dll - 
- libharfbuzz-0.dll - 
I changed these libraries in RT 5.5 for those for coming from RT 5.0-r1-gtk2_WinXP_32. and now I can run RT 5.5.
It is still there a small problem with the context menu - the message  pops up but after it is closed, RT 5.5 starts.
Thank you gaaned92 for your work.
Best wishes and happy New Year:
ps. [*] number on the screenshot