Why do I get this error when refreshing a Dataset?

An error occurred in the ‘Transform File from 2017 Year to date reports’ query. DataSource.NotFound: Excel Workbook: The 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine. The 64-bit version of the Access Database Engine 2010 Access Database Engine OLEDB provider may be required to read '2017 Apr - YearToDateReport.csv'. To download the client software, visit the following site: https://go.microsoft.com/fwlink/?LinkID=285987.

I created a report in November last year and when I was editing the queries, etc during setup everything ran fine. This year I added a couple of files into the folder the report pointed to and when I went to refresh I received the above message (but whether thats down to the 2 files I added or not I don't know). I've done some searching and found info in threads in previous years but can't find a solution.

We need to run the Database engine at 32bit for other software (and as I said there wasn't any issue last year when running it).

I don't know if its because I'm new to Power BI or not, but what I'm puzzled about is why did it work last yeart but not now?

Anyone else experiencing this?