encrypter skill

Hi

i want to write a skill to encrypt my skill file but my code doenst wok.. please help..

here is my code:

 (defun encrypt () 

file = axlDMFileBrowse(nil nil ?optFilters "Skill files(*.il)|*.csf|Dat files(*.dat)|*.dat|)("?title"Select Skill file to Encrypt"))

if(!isDir("~/skill/encrypt") then 

   createDir("~/skill/encrypt")

) 

fileparts = axlDMFileParts(file)

filepartsFileWext = nth(2 fileparts)

fileEncParts = strcat("~/skill/encrypt/" filepartsFileWext) 

encrypt(file fileEncParts eLock)

    )

axlCmdRegister("encrypt" 'encrypt)