SS2 Intermittent Multiplayer Loading Problem

[67241a2d4257aDafodarian]

Good morning everyone.

I'm sorry to bother you, but a friend and I are trying to play SS2 together, over a LAN. Both our computers happily run the game in SP mode, and generally when we start a fresh game it synchronises just fine. However, we have intermittent problems where the host computer will zip through the loading screen while the guest crashes when trying to load saves.

This would not be so perplexing, except that it affects all our saves (so is unlikely to be a corrupt file) and that it occasionally does not happen, and the game works fine. If SS wasn't so good, we'd probably just abandon it, but I'd love to be able to sort out the problem under the circumstances.

We've tried:
Starting a new game, then loading after reaching Cryo Recovery B
Loading from the multiplayer menu
Using Hamachi as a LAN
Unplugging our router from the internet before starting (improves our load-times, but no other change)
Taking turns at hosting

And probably other things too, we've been working on this one for a while.
We're both using a clean, mod-ready install from original CDs (Yes, I have two - I really like this game) with SHTUP and Rebirth - He has the Anomalous Bugs and Discrepancies, but it's not active according to SS2MM. We've run the SS2Tool over them, and dealt with the inventory bug as the multiplayer thread recommended.

All in all, I can't see why it's not working. Any suggestions, other than 'keep trying until you get a load that works despite no recognisable alteration in procedure'?