I had this problem as well.
I odined a fresh prerooted install of EC05, & could not install my apps from titanium backup, it reported that internal memory was low. There was no text's or anything else on te phone, it restored half of them then refused the others. My internal memory showed about half of it free & sd has lots of room. All apps that can move are already moved to SD.
I reflashed back to EB13, flashed the EC05 modem, & restored my apps with no problems. Even have room for more still. I don't know what is causing the issue but I tried 4 times with the same result.
I was useing the EXT4 version, maybe I'll try again with the plain jane cwm2 version.