Well, I've tried installing lvlibsvm-0.4.0.1 on both LabVIEW 2014/2015 32-bit and 64-bit now, and both seem to work for me.
The vip package contains both the 32-bit and 64-bit DLLs, which are both installed into "..\LabVIEW 201#\vi.lib\oysstu\LVLibSVM\bin" under x86 and x64 folders, respectively. I then execute a post-build script, which deletes the folder of DLLs not needed. The library is then mass-compiled (again) to correctly locate the DLL. The post-build script can be found on github (link). This is my first time using VIPM, so I'm not sure where the error lies as I'm unable to reproduce the problem on my end.
Just to make sure, you have installed the library using the vip file under releases, right? If you simply download the zip archive, you do not get any binaries - and would have to build it yourselves.
Edit: I've attached a zip containing the binaries temporarily until this can be resolved. Note that LabVIEW does not play nice with 32/64-bit dlls that has the same name (which is why the uneeded DLLs are deleted in the first place).
Edit 2: Removed the attached binaries, as they were outdated. The binaries are now released in a standalone zip archive in addition to the vipm file, see github for download.