get error from running any command on RnBeads when reopen R

Question

[sugus]

Hi there, I am learning how to use RnBeads to perform methylation analysis and make some practise from RnBeads.pdf document. Last night I have get some results and save my R image like:

save.image(file="F:/Bioinformatics/Su/test/test.RData")

When I reopen my R from test.RData this morning, it seems all data exist in R enviroment including Directory path and intermediate results. However, I cannot run any command, if so I get an error like:

nrow(meth(rnb.set.unfiltered)) # the number of sites in the unfiltered object
Error: Not all file.access(filename, 0) == 0 is TRUE

For now, I have no idea how to continue my work if I have to shut down R. It seems that I have to clear my report and start over. Thus is there something missing when I want to save the result that already get?

Thanks for anyone who could give me a gint and I am gonna start over now :(