OSM Composer V 0.83

I have not been able to get OSM Composer to function on my Laptop for some time although everything seems to be OK.
I came so frustrated that I deleted it completly and downloaded anew. Everything went just as described in the

Vereinfachte Installation
Die vereinfachte Installation nutzt die Autokonfiguration von Composer zusammen mit einem Minimalsatz der benötigten Werkzeuge. Diese Installation sollte ohne weitere Änderungen lauffähig sein und die erste Karte erzeugen können.
Voraussetzung: Java 1.6 muß installiert sein.
Composer downloaden und in ein beliebiges Verzeichnis entpacken.
Starthilfe-Set downloaden und in dasselbe Verzeichnis entpacken (ca. 6 MB).
Composer mit start.bat starten, es sollte die Meldung erscheinen “Autokonfiguration erfolgreich ausgeführt”.
Eintrag “Karte bauen” auswählen.
Button “Generieren” drücken und warten bis die Karte erstellt wird.

Starting map generation
Testing Mapsource
Removing MapSource registry values
calling Registry remove
Saving table Settings
Saving table ConvertRule
Saving table ConvertAction
Saving table IDManager
Checking for local data files.
Starting region Wandergegend
Local file is current: Wandergegend_data.osm
Finished region Wandergegend
Creating map
Saving table Outline
Saving table IDManager
Existing contours are current: Wandergegend_00110_0496_6_3_contour.osm
Splitting region Wandergegend
Generating style in C:\Java\OSM Composer\data\mapstyle
Calling mkgmap to create map
Build the garmin maps
calling mkgmap
mkgmap call failed!
Generation finished
Saving table Settings
Saving table MapItem
Saving table IDManager

As you see the mkgmap call failed.

The path to mkgmap in “Einstellungen” is C:\Java\OSM Composer\Tools\mkgmap.jar and it is there. I have just checked it.

This is not the only problem I am having:
java.lang.illegal\ArgumentException:index capacity exceeded 100nnnnnn where n is a number between 0 and 9
I have incresed XmxnnnM to 700 to no avail. (1024 resulted in the composer not even starting)

also I get

java.lang.ArrayindexOutOfBounds Exception -1

I have been working on this for weeks now. As I said: It works OK on my desktop computer but I cannot take that to Portugal this week.

Anybody got any ideas of what I am doing wrong!!!