Why doesn't my flash works after masking it

Tweet

hi, everyone.. I need ur help urgently. This discussion is with regards to macromedia flash files. I used masking layers in my flash files. But it does not seems to work. Meaning after i mask the layers, the image does not show in the flash and also, the text that i mask, didnt appear despite i embed the characters. Is there something wrong with my programme? Or is there something wrong with the way i do? But it used to be fine. ANyone encounter the same problem? Btw, im quite new in web designing. Can anyone introduce me a good book that is available in singapore, so that i can pick up skills in flash more efficiently... Thank you!