Error: 404 Not Found

Sorry, the requested URL 'http://e-onbatteries.com/index.php/catalog/product_compare/add/product/31/uenc/aHR0cDovL2Utb25iYXR0ZXJpZXMuY29tL2luZGV4LnBocC9mbGVldC1hbmQtc2FmZXR5Lmh0bWw_ZGlyPWRlc2Mmb3JkZXI9cG9zaXRpb24%2C/form_key/sThhRXXuVvN3bC0x/' caused an error:

Not found: '/index.php/catalog/product_compare/add/product/31/uenc/aHR0cDovL2Utb25iYXR0ZXJpZXMuY29tL2luZGV4LnBocC9mbGVldC1hbmQtc2FmZXR5Lmh0bWw_ZGlyPWRlc2Mmb3JkZXI9cG9zaXRpb24,/form_key/sThhRXXuVvN3bC0x/'