Canon parweshor s400 ixus

First of all have you seen the answers you got on a parallel post? -
http://www.fixya.com/problems-solutions/...
Some good suggestions there.

Always try to leave the battery charging until fully charged.
Batteries like to be fully charged and then fully drained, it's not 100% causing this specific problem, but it will prolong your battery life.

Certain small brands for memory cards can have compatibility problems with some cameras, including a "card locked" message, when the card isn't locked. The big brands(kingston, sandisk etc) will usually work fine and fast with all cameras. Pretec is also pretty good.

Try using another card, and see if the problem persists.
And don't completely rule out the possibility that you have the card locked... ;]

Good luck

While i have now solution to this problem i have some more info for those who may....i have a a620 and two SanDisk 512 SD memory cards (both with the same serial: AX0620502617D) and both the cards did the same thing...gave me a card locked message. I looked and both cards are unlocked......i have a hard time believing the fact that TWO cards from the same manufacture did that exact same thing.