It seems that unix behaves strangely with ! in folder names. I believe glftpd had a similar problem. I suspect it's the ftp server as other servers do not experience this.
dont know if you remember me, but anyway, can you confirm glftpd has this problem (i was not able to reproduce it)? If this is the case i would like to know how i can reproduce this so i can maybe fix this issue in a future release.