Why no incrementals in degraded mode?

Hello!

Since I have re-installed amanda, I get no more incrementals when it runs
into degraded mode.  From the logfiles I can't find any hint why it always
does full-backups.  All DLEs are affected by this problem.  But in the
description below, I list only one DLE.

Here is what "amadmin info" says about the DLE in question:


  Current info for host.do.main /var:
    Stats: dump rates (kps), Full:  886.0, 768.0, 963.0
                      Incremental:   -1.0,  -1.0,  -1.0
            compressed size, Full:  42.8%, 42.9%, 42.9%
                      Incremental: -100.0%,-100.0%,-100.0%
    Dumps: lev datestmp  tape             file   origK   compK secs
            0  20060120                      0  416110  178150  201


Here are the relevant excerpts (reformatted to improve readability) from
amdump.1:


  reserving 9437184 out of 9437184 for degraded-mode dumps


I don't use the "reserved" keyword, so no full-dumps should be done in
degraded mode.  That much looks OK.


  driver: result time 0.474 from taper: TAPE-ERROR
          [label PPC02 or new tape not found in rack]
  dump of driver schedule before start degraded mode:
  --------
  --------
  dump of driver schedule after start degraded mode:
  --------
  --------


Since no tape was found, degraded mode should be entered?  But what do the
empty driver scedules mean?


  planner: time 433.680: got result for host host.do.main disk /var:
           0 -> 428820K,
           1 -> 45610K,
           -1 -> -2K


The estimates look reasonable to me.


  FAILED QUEUE: empty
  DONE QUEUE:
    0: host.do.main /var
    [ ... More DLEs deleted. They all are handled the same ... ]
  
  ANALYZING ESTIMATES...
  pondering host.do.main:/var... next_level0 -1 last_level 0
            (due for level 0) (picking inclevel for degraded mode)
            picklev: last night 0, so tonight level 1 
    curr level 0 size 182652 total size 182898 total_lev0 182652 
balanced-lev0size 182652


So the "pondering" line says that I should get level 1?  But what does the 
"curr level"
line say?  Looks like level 0 is already picked?  Why?


  INITIAL SCHEDULE (size 5209107):
    host.do.main /var pri 2 lev 0 size 182652

  DELAYING DUMPS IF NEEDED, total_size 5209107, tape length 9113600 mark 50
    delay: Total size now 5209107.

  PROMOTING DUMPS IF NEEDED, total_lev0 5208533, balanced_size 5208533...
  planner: time 433.726: analysis took 0.045 secs

  GENERATING SCHEDULE:
  --------
  DUMP raven.wolf.local fffffeff9ffe7f /var 20060120 2 0 1970:1:1:0:0:0 182652 
214 1 2006:1:19:2:7:50 22805 760
  --------


Here we go: full dump is choosen. 

Any ideas?