www/firefox3 crashes on sparc64

[raymond.meyer%rambler.ru@localhost]

Hi, I'm running NetBSD 5.0_BETA on sparc64. Firefox crashes on this 
architecture when browsing some websites (e.g. facebook.com). I don't know much 
about C++, so maybe someone can help me with the following backtrace:

Core was generated by `firefox-bin'.
Program terminated with signal 10, Bus error.
#0  0x00000000417071c8 in nsCSSValue (this=0x4e6e1724, aCopy=@0x4e68f060)
    at nsCSSValue.cpp:137
137     nsCSSValue.cpp: No such file or directory.
        in nsCSSValue.cpp
(gdb) 

Below is the code fragment from nsCSSValue.cpp file:

nsCSSValue::nsCSSValue(const nsCSSValue& aCopy)
  : mUnit(aCopy.mUnit)
{
  if (mUnit <= eCSSUnit_Dummy) {
    // nothing to do, but put this important case first
  }
  else if (eCSSUnit_Percent <= mUnit) {  
    mValue.mFloat = aCopy.mValue.mFloat;
  }
  else if (eCSSUnit_String <= mUnit && mUnit <= eCSSUnit_Attr) {
    mValue.mString = aCopy.mValue.mString;
    mValue.mString->AddRef(); 
  }

Crash happens on line 137, which contains:
        mValue.mString = aCopy.mValue.mString;

Looks like the code does a misaligned read on sparc64 and crashes with Bus 
error. Can anyone suggest a patch to fix this?