r4383: in order to cope with overfilled buffers on trans2 findfirst we need to use...

r4383: in order to cope with overfilled buffers on trans2 findfirst we need to use 32 bit offsets and lengths
in trans2 fill code, even though the packets themselves can only use 16 bit lengths. This prevents
the overflow detection code from failing due to 16 bit length wrap.
(This used to be commit 5cd74c22e99bc78e1f3ddf3f098790c4b4b87b4f)