We have that very same issue running TSM 4.1.2.14 on AIX 4.3 with TSM 4.1.4
running on OS/390 V2R9.  Traces yield different results the few times the
hang occurred while trace was activated.  Most times it doesn't hang at all
with trace active.  Archive sessions do run SLOWWWW!

We are currently working with IBM.  They are now going to bring a
Performance person to the conference call.  Archives running in macro files
worked fine in ADSM 3.1.06.  After moving to TSM 4.1.2.14 the hangs
occurred.  IBM suggested that when we install TSM 4.2.0, then re-write the
process to take advantage of a filelist feature, bundling numerous(the more,
the better) file archives in one archive session.  This failed in TSM
4.12.0, so IBM then suggested that we install TSM 4.2.1.  The failures don't
occur as often, but the hangs still do from time to time.

This has been a "Moving Target", so problem determination is almost
impossible.

How many archives are being done per day at your site?  IBM tells us that we
were doing too many for TSM 4.x archive to handle.