I would suggest 2.32 version first.
You have to install a C compiler before configuring 2.22 build.
I think that finding the optware 2.22 version directly as a package from the internet, and installing it as usual with
/opt/bin/ipkg install XXX
where XXX = the name of the ipk downloaded
would be much easier than building from source code.
Previous builds of transmission are here, hopefully they are compatible with My Book
Download the version that you want. If you cannot downgrade for a reason, first back up your transmission settings, delete the new version, than install the old version.