Error in R-Plot

I am using the R-scripting nodes for a while now and they are very useful to my research. But recently, every plot I want to make gives me an error. It is executed (light is green), but when I want to look at the view I get this error:

ERROR R Plot     View instantiation failed: null

I added my logfile from my latest knime session to this post. I hope somebody can help me.

I also put the information on my blog:


Hi Kris


I checked your logs. So far I can only suspect what went wrong: I'm guessing, that the image that is created during the execution of the RplotNode can't be accessed once the node tries to create it's view. Now how exactly this is coming about is hard to see from the error message or the log.


on your blog I saw, that you used the following script in the RplotNode


but kIn is a R dataframe that most of the time can't be put directly into a plot function. Try to fork the input to your RplotNode into an openInR node too and execute it. Then a R console should pop up. When you type 


... in there R displays the dataframe. Play around with the dataframe in the console until you get to plot the data as you like. Then use these commands and paste them back into the RplotNode. This than has more chances to work.




Where are the images saved? Is there a way to change that?

And no, I also get this error when I try to do your boxplot with the iris data file.

The one from your template.

So I suppose there must be another error somewhere...



Hi Kris,

that's weird. Which R version do you use and is the Rserver locally installed or remote? I also have strange problems since a few days (and my colleague too). In my case the RPlot node fails if I use the local RServer. But I get a different error message:

ERROR     R Snippet     DataSpec generated by configure does not match spec after execution.
ERROR     R Plot     Execute failed: eval failed

I tried to debug this behaviour but I couldn't figure it out yet. The strange thing is that the plot works if I open an R-session ('Open in R' node) and copy paste the script...

We try to find out what's going wrong.


Ciao, Antje

Hi Antje,

I use R-2.12.2 and my rServe is locally installed.

I just wanted to say that I got a workaround my initial error. In the tab output options it is possible to set a location for the image to save. (which I never had to to before, but it works)

For your problem, I remember seeing that error myself too, but I never bothered much with it. I'll see if I get it again what I did.


There are some issues with the older versions of Rserve.

make sure you have 0.6-2 or higher.