[BioC] MedlineR - Error in xmlRoot

[Andrej Kastrin]

Dear all,

I think it's better to post here, instead on r-help. It's about MedlineR 
package in R; I receive the following error message when using 
"getAmatrix" (co-occurance matrix between terms in PubMed) command:

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=GLB1+AND+ARSA
Error in xmlRoot(result.xml) : no applicable method for "xmlRoot"

Andrej