Hmm, that's odd.
I use Easy1541 (from Aminet) with it's interface quite regularly on my A1200.
The specs of that machine are:
A1200 with Blizzard 1230IV and 16MB of fast ram.
2.something GB 3.5inch HDD (Powerflyer)
and OS 3.5. (KS 3.1, PAL)
Methinks it should work on your system too?
Perhaps it doesn't like OS 3.9, but other than that I wouldn't know.
I do know it doesn't really like other programs running at the same time, so perhaps lose some commodities or something?