What should i keep in mind when uploading a script?

Please ensure that the script is transferred using the ASCII mode of your FTP program.
A transfer in binary mode can cause a script failure on the web server (error 500).

Background:
Unfortunately, several operating systems use different symbol sequences to mark the end of a line. On Windows-based systems, a carriage-return Linefeed (CRLF) is used most of the time, whereas Unix-based operating systems use only a LF. Your script cannot be executed if it is only uploaded to our servers with "CRLF" line breaks.

FTP programs differentiate between binary mode (the file will be transferred exactly as it is stored) and ASCII-mode.
In ASCII-mode, the FTP program will adjust the line ends of the file during the transfer from the source system to the target system.

Further information on the subject of SFTP can be found here.