Add notes re java version & windows paths.

Fixes #25.

doc/user-guide.adoc

@@ -31,7 +31,7 @@ To run the pipeline properly, a system equipped with and able to handle at least
 
 Furthermore, the  pipeline depends on a *internet connection* when running to download the models for the current configuration. *It does not work off line!*
 
-The pipeline requires *Java 1.8* or higher. You can download Java from the http://www.oracle.com/technetwork/java/javase/downloads/jre8-downloads-2133155.html[Oracle website]. You can check your current Java version by running `java -version` in your command line.
+The pipeline requires *Java 1.8* or higher. You can download Java from the http://www.oracle.com/technetwork/java/javase/downloads/jre8-downloads-2133155.html[Oracle website]. You can check your current Java version by running `java -version` in your command line. You should use the *64 bit* version of Java in order to be able to allocate ≥ 4 GB of RAM.
 
 == Running the Pipeline
 
@@ -193,7 +193,9 @@ posTaggerArguments = executablePath,string,C:/tree-tagger/bin/tree-tagger.exe,\
 useLemmatizer = false
 ----
 
-Change the paths for the parameter _executablePath_ and _modelLocation_ to the correct paths on your machine. You can then use TreeTagger in your pipeline using the `-config` argument:
+Change the paths for the parameter _executablePath_ and _modelLocation_ to the correct paths on your machine. Beware these values are case sensitive even on Windows – when unsure, copy & paste the paths from Explorer. 
+
+You can then use TreeTagger in your pipeline using the `-config` argument:
 
 [subs="attributes"]
 ----