Hi, I'm trying to use your MedlineR library but I get an error. I've tried on Windows and Linux and it is the same error: Error in xmlTreeParse(file = query, isURL = T) : error in creating parser for http://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&rettype=count&term=STE18+AND+STE12 Error in xmlRoot(result.xml) : no applicable method for "xmlRoot" I'm wondering if it might be because we are behind a proxy but I don't know how to declare it. Yours sincerely, Nolwenn Le Meur Faculté de médecine INSERM U533 NANTES -FRANCE