If the download with the gaps was 32 bit with the download script, the problems have likely the same reason and are not related to 64 bit. It looks like a random stalling of the server. We had so far never a problem with the FXCM history, on the contrary, it was a rather reliable source.

I've forwarded the problem to the plugin developer. If we cannot reproduce it here, we will send you a special diagnostics version of the plugin that logs details of the problem.