What is the capacity of the removable memory card (SD or SDHC card) installed in the camcorder? How long were you trying to record for?
According to the user guide a 4GB card should give you approximately 30 minutes of full HD recording time (FXP mode) or up to 90 minutes in LP mode. Obviously a smaller capacity card will give you less.
As best that I can determine the maximum capacity card that the camera supports is 16GB. If you use this it should give you 2 hours of full HD video recording time.
I do not know why the camera would still keep audio recording if there was not enough storage space in the SD card to keep on video recording. I suggest that if you do have a low capacity card e.g. 1GB or 2GB that you upgrade to a 4 or 8GB and see if the problem still occurs. Alternatively try recording in a lower resolution mode to extend the amount of time that you can record
There was a firmware update for your camcorder released in 2011 which allows recording of movies in FXP mode when using a Class 10 SD or SDHC card. (Class 10 cards were incompatible with the camcorder when using FXP mode before). Here is a link to the firmware update page. Click on Firmware https://www.usa.canon.com/internet/porta...