The SD card contains video footage. I checked it out on the camera and I can view the files perfectly. When I want to view on my PC via a A USB card reader, the PC asks me to format the isc to enable me to view.
It could be that your SD card is of a 'family' that is not supported by your reader.
SD cards can be SD, SDHX, SDXC, or SDIO. A reader only capable of SD or SDHC will not be able to read an SDXC card. AN SDXC capable reader is backwards compatible and would read SD, SDHC, and SDXC.