Path to PEAR

I have created an email contact form.
I am using the settings as recommended by 1and1.co.uk.

If I use these setting on my local PC using xampp then the test emails arrive as expected.

When I upload to my 1and1 server the the emails do not arrive.

The Path to PEAR box is not filled in as you can see. I have asked 1and1 support if this need to be completed but cannot seem to get an answer.

Can you say if the Path to PEAR needs to be included or can you see if there may be some other reason I cannot seem to use the remote server for this?

I attach an image which shows the settings.

Later:
I have been contacted by 1and1 support who ask

Can you please specify what is "Path to Pear ? Is it a folder in your Outlook or is it part of the email settings? We need to clarify the information first before we can provide the resolution.

Later still!
1and1 suggest the path to PEAR is perhaps
C:\Program Files\Parallels\Plesk\Additional\PleskPHP5\pear\ .
I used this in the UE envelope box and uploaded the files but still the email failed to arrive?

BTW I am on the 1and1.co.uk shared server maybe this is the problem


Many thanks for any assistance

John