Email problem following Sugar update

[franckt]

I was working perfectly with sugarce 5.2.0k
I update today to 5.5.1 version.

Wherever, I want to compose an email (from subpanel link or subpanel button or from direct link on an email fiel in a detail view for example), I got an error :

Here it is the url where there is an error :
http://localhost/sugartest/index.php..._type=Accounts

its html answer :
<link rel="stylesheet" href="custom/themes/Sugar/mycss.css" type="text/css" media="screen" />{"to_email_addrs":"<info@roger.com>","parent_type ":"Accounts","parent_id":"4c575e7e-8611-1d97-7be7-4bb9d95983ca","parent_name":"Test","subject":"","b ody":"","attachments":[],"email_id":""}

On Firebug, it's said a problem on
parseJSON
http://localhost/sugartest/include/j...ode=1389485375
Line 9335


Anyone can help me ?
Thanks

Franck

My config :
Apache 2.2.11
Php : 5.2.8
Mysql : 5.1.30