SD card error.

[SheKungFu]

My fiancé and I own the same phone (MyTouch 3G) and we are both having the same issue. When we purchased the phones we quickly found out that we were unable to take pictures or video. This was because the phone was giving us an SD card error. Stating that we had to insert and SD card. Our SD cards were both already inserted. We then decided that since they were new cards there wouldn't be any harm in reformatting and seeing if the phone would then recognize them. It didn't. We called HTC and both received new SD cards. Now our problem is that if we go to take video or pictures, the phone will recognize the SD cards for the first few photos or videos but when you go to take the third or fourth it will give us the same error about the SD card that we initially had. The only way to solve this problem that we have found is to shut our phones off and turn them back on...but again this is only a temporary fix because we will only be able to take a couple more pictures or videos. Anyone know how to solve this issue permanently?!?!