"I can import the files as a binary file using the user input dialog, but I get weird results"
Just to check - what you mean here is that you cannot import as PolyView, but you can as 'raw' binary, is that correct?
Assuming it is, a raw binary file is assumed to be made up of a header, followed by data for a given number of channels interleaved together so that for a three channel file the data items would be arranged thus:
Channel 1, Channel 2, Channel 3, Channel 1, Channel 2, Channel 3 ...
You have to specify the header size correctly and set the number of channels to match what is present, and you also have to specify the sampling rate to match how the data was collected - as this is raw binary the importer cannot determine these values itself. So, it may be that you have not entered these values correctly (and it may also be the case that PolyView data is not structured in the correct manner). Looking at your picture, that waveform looks plausible but it appears to be made up of signals from multiple channels mixed together - so it may simply be that you have not entered the correct number of data channels.
You may want to experiment with getting the raw binary importer to work properly, but I imagine you would be much happier if you could use the PolyView importer as it will set up everything correctly. To do this you need an improved importer, one that does not fail. The first thing to do is to make sure you are running the latest release of your version of Spike2 - you can download a suitable update installer from the main CED web site.
If that does not work it may be that we have not found whatever fault in the importer is causing this. The first step is for you to reply to this post, telling me the exact version number of the copy of Spike2 that you are using. I will then be able to investigate and see if we appear to have fixed this, if not we may need a copy of your data file so that we can work on this.