If it hasn't already been done, please drop MDAC dependencies (e.g. Microsoft.Jet.OLEDB.4.0) in the next release. I just lost four hours to this:
https://www.nopcommerce.com/boards/t/8060/aspnet-codebehind-error-could-not-load-type-when-adding-a-new-folder-and-defaultaspx.aspx
.. because I tried to force x86 and the project would not compile properly. I don't know why it didn't compile properly, but that's really not the point. .NET is x86/x64 neutral by default and I should not have to be worrying about this. I also may be using heavy object caching, taking advantage of large memory on the server, and x86 would cripple this capability.
There are plenty of open source Excel import and export tools. Here's one of the prominent ones:
http://epplus.codeplex.com