problem of installation of spip

I have tried to install spip by "mysite.org/write" it gives me this message :
Parse error : syntax error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or ’}’ in /homepages/42/d332126811/htdocs/stvictor/ecrire/public/interfaces.php on line 51
I have added the sentance for php5, no succes !!
thanks for answers