To use Php5Php5 with OVH, transfer your scripts with the beta extension via ftp. For example:
For more information on ftp transfers: FtpUsage
Php functions in suexec, in other words, that it is executed with the rights of your ftp account. Via php you have exactly the same rights via ftp. So then you do not need chmod 755 superior permission.
More information on permissions: FtpProblemFtpProblem
If your script does not have proper permission or you come across the 505 error (Internal Server Error), the problem is from the configuration of your scripts. Here is the guide that will help you find the origin of the problem: InternalServerError