the problem with Acer Aspire 5553G keyboard and touchpad in Linux is not new. Try to google for "Ubuntu linux on Acer Aspire 5553G keyboard not working" (remove the quotes when googling). It's good to search Ubuntu forums too (after all, BT5 is based on Ubuntu 10.04).
Here's what I found after quick googling:
This link leads me to this solution on ubuntuforums.
On short, it seems a BIOS update could solve your keyboard/touchpad issue.
I recommend you to google more on this issue and, if confirmed from multiple sources, try the BIOS update.
Check the links I gave you, there's all the BIOS update information there(link for the BIOS image, required BIOS version, etc) ...