[R-SIG-Mac] Blank screen on a mac when plotting some (but not all) data

[Pearson, Aislinn]

Hi,

I am analysing some data using ANOVA and I want to check that all of my assumptions are correct (constant variance, normal distribution of errors, etc). I understand from Mick Crawley's 'Statistics: An introduction using R" that the best way to do this is to use plot(model):

model<-aov(Total.Distance_Log~Treatment)
summary(model)
plot(model)

There are no problems writing the model or summarising it. However, when I try to plot it using the above code the image window for the graph is empty. The console gives the instruction to hit return to see the next graph, but this doesn't seem to generate anything either. I know that the image window works because I was using it to create histograms as an alternative way of checking that the data is normally distributed:

hist(Total.Distance_Log)

I also think plot(model) works as I asked a colleague to check it on his PC. 

I have had a look on the wiki, but haven't found anything yet. If anyone knows what I am doing wrong I would be grateful for some advice.

Thank you