plugin crash on Linux 64bits with Maya 8.5 SP1

I have a strange crash with a custom MPxNode in maya on Linux 64bit.
This plugin works find on win 32, win 64 and linux 32 but crashes on Linux 64.

I have isolate the probleme, but i don't know why this part of code crash on
Linux 64 :

Here is the crashing part of the code :

MDataHandle filePathHnd = data.inputValue( filePath );
  MDataHandle localFilePathHnd = data.inputValue( localFilePath );
  MDataHandle useLocalFileHnd = data.inputValue( useLocalFile );

  // reference file path
  MString rFP = filePathHnd.asString();
  // local reference file path
  MString lRFP = localFilePathHnd.asString();
  // use local File Flag
  bool uLF = useLocalFileHnd.asBool();

I also found a solution for this example, which is to retrieve my MString datas
one by one, as below :

  // reference file path
  MDataHandle filePathHnd = data.inputValue( filePath );
  MString rFP = filePathHnd.asString();
  // local reference file path
  MDataHandle localFilePathHnd = data.inputValue( localFilePath );
  MString lRFP = localFilePathHnd.asString();
  // use local File Flag
  MDataHandle useLocalFileHnd = data.inputValue( useLocalFile );
  bool uLF = useLocalFileHnd.asBool();


But this solution, despite preventing data access crash, is not acceptable as I
have to deal with more complex attributs such as arrays.
Not to mention the fact that I'm not sure Maya is still stable after using this
workaround...

Has someone ever met this problem ? I saw a post about that somewhere on the web
but the poster just mentionned he found the solution himself, by playing with
gcc flags, and did not reveal it...

Regards, 



command port delivery an error :

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 46912682359376 (LWP 8938)]
0x00002aaaad82b592 in TdataBlock::hasPlugCache ()
 from /usr/autodesk/maya8.5-x64/lib/libDependEngine.so 



Configuration :

/Linux 64 :
CentOS 5.0 Base on  Red Hat Enterprise Linux 5.0
Intel(R) Core(TM)2 CPU          6700  @ 2.66GHz
QuadroFX 3500
Maya 8.5 SP1

Linux 32 :
CentOS 5.0 Base on Red Hat Enterprise Linux 5.0
Intel(R) Xeon(TM) CPU 2.80GHz
VGA compatible controller: ATI Technologies Inc Rage XL
Maya 8.5 SP1/

I use to compile :
/gcc version 4.1.1 20070105 (Red Hat 4.1.1-52)
and option  :
-fPIC -m64 -O3 -mtune=generic -pthread  -pipe  -DLINUX -D_BOOL -DREQUIRE_