'maven rebuild' fails, but 'maven build' works?

[Jacek Laskowski]

Hey,
Doing 'maven rebuild' the build failed, but 'maven build' finished 
properly. I've seen it several times - although 'maven rebuild' failed 
(with all the libs downloaded) 'maven build' worked well.

I understand that sometimes when there're libs that aren't downloaded or 
built maven may fail, but as you may have seen it's not the case now.

default:
build:
assemble:
    [mkdir] Created dir: C:\projects\geronimo\target\lib
    [copy] Copying 1 file to C:\projects\geronimo\target\lib
    [copy] Copying 1 file to C:\projects\geronimo\target\lib
    [copy] Copying 1 file to C:\projects\geronimo\target\lib
    [copy] Copying 1 file to C:\projects\geronimo\target\lib
    [copy] Copying 1 file to C:\projects\geronimo\target\lib
    [copy] Copying 1 file to C:\projects\geronimo\target\lib
    [copy] Copying 1 file to C:\projects\geronimo\target\lib
    [copy] Copying 1 file to C:\projects\geronimo\target\lib
    [copy] Copying 1 file to C:\projects\geronimo\target\lib
    [copy] Copying 1 file to C:\projects\geronimo\target\lib
    [copy] Copying 1 file to C:\projects\geronimo\target\lib
    [copy] Copying 1 file to C:\projects\geronimo\target\lib
    [mkdir] Created dir: C:\projects\geronimo\target\schema
    [copy] Copying 15 files to C:\projects\geronimo\target\schema
    [mkdir] Created dir: C:\projects\geronimo\target\repository
    [copy] Copying 56 files to C:\projects\geronimo\target\repository
    [echo] Bootstrapping service deployer
    [mkdir] Created dir: C:\projects\geronimo\target\bin
    [mkdir] Created dir: C:\projects\geronimo\target\config-store
BUILD FAILED
File...... file:/c:/projects/geronimo/
Element... maven:reactor
Line...... 179
Column.... 27
Unable to obtain goal [default] -- 
file:/c:/projects/geronimo/modules/assembly/:115:37: <define:jellybean> 
java.lang.NullPointerException
Total time: 23 minutes 6 seconds
Finished at: Wed Feb 25 16:24:20 CET 2004

but
test:prepare-filesystem:
    [mkdir] Created dir: 
C:\projects\geronimo\modules\maven-plugin\target\test-classes
    [mkdir] Created dir: 
C:\projects\geronimo\modules\maven-plugin\target\test-reports

test:test-resources:
test:compile:
    [echo] No test source files to compile.
test:test:
    [echo] No tests to run.
jar:jar:
    [jar] Building jar: 
C:\projects\geronimo\modules\maven-plugin\target\geronimo-deployment-plugin-DEV.jar

    [copy] Copying 1 file to C:\Documents and 
Settings\jl540585\.maven\repository\geronimo\plugins
BUILD SUCCESSFUL
Total time: 7 minutes 41 seconds
Finished at: Wed Feb 25 16:36:49 CET 2004

Cheers,
Jacek