To be honest - I have exactly the same problem. Well, maybe not "exactly".
I'm loading the very small test program (BTW Symbol Loader now stops at entry point!), do bpm x and it is OK! Later on I do bpx MessageBoxA (bl shows me that everything is OK and I have NTSYMBOLS = ON and I have a valid path to user32.dll in my winice.dat) and NOTHING happens.
I don't think it is a bug in Soft-Ice. I might be missing something... I don't know what

((
BTW - usual bpx on a certain address is working fine!