losing data when switching between wysiwyg and text edit mode

hi, i have a long xwiki page that spans several screens. when i try to edit sections of the page some of my data (escpecially code blocks {code}) disappear when i save them. this happens always during switches between edit modes. has anyone experienced the same problem? i'm using xwiki 1.0-rc2. If necessary i can provide my exported page to reproduce the error. g, kris