Problem with AIX: shared libraries aren't loaded

Hello guys, I have a trouble when running an application in AIX, I've compiled and the
LIBRARY_PATH seems ok, but I get the following message:

rtld: 0712-001 Symbol __pthread was referenced
      from module main_app(), but a runtime definition
            of the symbol was not found

ldd and dump -Tv doesn't report any trouble

[25]    0x00000000    undef      IMP     DS EXTref libpthreads.a(shr_xpg5.o) 
__pth_init
[26]    0x00000000    undef      IMP     BS EXTref libpthreads.a(shr_xpg5.o) 
__pthread

I've tried some parameters (-bexpall) but nothing works, please give me some clue

thanks in advance

Which version AIX and technology level?

Aix: 5.3.00

>lslpp -l | grep -i "Compiler"
  vac.C                     10.1.0.0  COMMITTED  IBM XL C Compiler
  vac.html.common.search    10.1.0.0  COMMITTED  XL C for AIX Compiler 
...

I didnt meet this error before but if your application is related oracle or sql , in my research this is a can bug and your system needed to upgrade Technology Level 7

I think it does

oslevel -s
5300-09-02-0849

indeed I'm using proC for my app however I have another old one that uses the same parameters for ProC and I don't get errors, what linking parameters must I consider?