The current ACR version is included in Lightroom v5.5 and should import your RAW files. The ACR plugin you mention is a Photoshop not Lightroom product.
Check the firmware version of your camera as I believe v1.1 was released July 8 and if that changed the RAW format LR may not recognize the newer version.
If you cannot import into LR 5.5, upload the image to Dropbox or similar and someone on the forum will test it on their LR for you.