参考自:stackoverflow
I've the same message, I have a webpage with do on visual studio 2010, I read a file.xls on that page,in my project visual has not any problem, when I put it on my IIS local throw me a'Microsoft.Jet.OLEDB.4.0' provider is not registered on the local machine' ,I fixed that problem next following this steps,
1.-Open IIS
2.-Change the appPool on Advanced Settings
3.-true to enable to 32-bit application.
and that's all
ps.I changed Configuration Manager to X86 on Active Solution Platform