@startuml does not work for all types of diagrams

[k3b]

when i embed diagrams with @startuml .. @enduml only sequence diagrams are shown (sometimes)

when i process this test-javadoc note: i get the same results when i add the missing " * "

/**
 * ![sequenceDiagram3 Diagram](sequenceDiagram3.png)
 *
 * ![sequenceDiagram2 Diagram](sequenceDiagram2.png)
 *
 * ![objectDiagram Diagram](objectDiagram.png)
 *
 * ![classDiagram Diagram](classDiagram.png)
 *
 * ![sequenceDiagram Diagram](sequenceDiagram.png)
 *
 * @startuml objectDiagram.png
 * title objectDiagram
 * object Object01
 * object Object02
 * object Object03
 * object Object04
 * object Object05
 * object Object06
 * object Object07
 * object Object08
 * 
 * Object01 <|-- Object02
 * Object03 *-- Object04
 * Object05 o-- "4" Object06
 * Object07 .. Object08 : some labels
 * @enduml
 *
 * @startuml classDiagram.png
 * title classDiagram
 * object ILocation
 * object IGeoPointInfo
 * object GeoPointDto
 * ILocation <-- IGeoPointInfo
 * IGeoPointInfo <-- GeoPointDto
 * @enduml
 *
 * @startuml sequenceDiagram.png
 * title sequenceDiagram
 * Alice -> Bob: Authentication Request
 * Bob --> Alice: Authentication Response
 * @enduml
 *
@startuml sequenceDiagram2.png
title sequenceDiagram2
(*) --> "First Activity"
"First Activity" --> (*)
@enduml

 *
@startuml sequenceDiagram3.png
title sequenceDiagram3
Alice -> Bob: Authentication Request
Bob --> Alice: Authentication Response
@enduml
 *
 */

generates

• sequenceDiagram3.png ok
• sequenceDiagram2.png err: Dot Executable: Null
• objectDiagram.png err: Dot Executable: Null
• classDiagram.png err: Dot Executable: Null
• sequenceDiagram.png ok

I am using

• 'ch.raffael.pegdown-doclet:pegdown-doclet:1.3'
• Graphviz2.38
• gradle-2.14
• win7-64(german)

[k3b]

Graphviz installation program did not set the windows environment variable "GRAPHVIZ_DOT"

after setting

• GRAPHVIZ_DOT=C:\Program Files (x86)\sdk\Graphviz2.38\bin\dot.exe

all worked as expected