PDF output with report type Report Builder

 Hello All,

While i was developing a custom report by Reports Builder with PDF format  'not XML format '  , it gave me the attached file with strange characters

I thought  maybe i have problem with Acrobat Reader or Reports Builder ,

But 

Eventually i discovered that there are PDF standard reports 'made by oracle' with the method Java Concurrent Program and it's output is PDF and it works well  ! ! 

 

 So my questions are:

 a.  How to solve these strange characters in the report ?

 b. Where is the strange characters issue comes from , from the Acrobat Reader in the DB Server or the one in the client PC ?