DEXSeq errors with the sample data

[bbm]

I'm going to use DEXSeq to analyses my PE data (honeybee genome, 3 reps of controls or trt, 3 time-points).

I tried the code for the drosophila sample data, and it showed an error in the end:

Error in gzfile(file, "wb") : cannot open the connection
In addition: Warning message:
In gzfile(file, "wb") :
cannot open compressed file '../data/pasillaDEXSeqDataSet.RData', probable reason 'No such file or directory'

Does this mean it cannot make a plot?

My gene expression data is from Tophat/Cuffdiff, and the splicing.diff file didn't show any hits/significance.

I don't know how to run HTseq or python, but I'm willing to learn more if I need.

Do I need to install python on my computer?

Sorry about these many questions... Thank you so much if you can help me!!!!