#include <clx.h>
#include <dlfcn.h>

#pragma hdrstop

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.xfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------

void __fastcall TForm1::Button1Click(TObject *Sender)
{
 void *handle;
 char *error;

 handle = dlopen("libcrypt.so", RTLD_LAZY | RTLD_GLOBAL);

 if(!handle)
 error = dlerror();

 if(error != NULL)
  MessageDlg(error, mtError, TMsgDlgButtons() << mbOk,  0 );

 error = dlerror();
 if(error != NULL)
  MessageDlg(error, mtError, TMsgDlgButtons() << mbOk,  0 );
}
//--------------------------------------------------------------------------- 

Это вылетает после

if(!handle)
 error = dlerror();

 if(error != NULL)
  MessageDlg(error, mtError, TMsgDlgButtons() << mbOk,  0 );

надо в начале 
handle = NULL; error = NULL;
затем 
 handle = dlopen("libcrypt.so", RTLD_LAZY | RTLD_GLOBAL);

if(handle == NULL)
 error = dlerror();

 if(error != NULL)
  MessageDlg(error, mtError, TMsgDlgButtons() << mbOk,  0 );