As discussed on valgrind-users in the thread
http://comments.gmane.org/gmane.comp.debugging.valgrind/7535
valgrinding Wine running a large win32 app (Picasa) fails with the message

vex: priv/host-x86/isel.c:510 (doHelperCall): Assertion
`typeOfIRExpr(env->type_env, args[i]) == Ity_I32' failed.

You can reproduce this by valgrinding the trivial C program

int main ( void ) {
 __asm__ __volatile__( "subw $0x28, %%sp\n"
                       "movl $0, 0(%%esp)\n"
                       "addw $0x28, %%sp" : : : "memory" );
}