problem in installation of extensions

while trying to run some examples frm the KNIme website, and tying to install some extensions the following problem comes again and again

ERROR R Snippet (Local) Execute failed: Execution of R script failed: Error in library(igraph) : there is no package called 'igraph'

ERROR R Snippet (Local) Execute failed: Execution of R script failed: cannot open compressed file 'C:\Users\smili\AppData\Local\Temp\RtmpK5QnJr/libloc_C%3a%2fUsers%2fsmili%2fDesktop%2fknime%2fknime_2.5.4%2fplugins%2forg.knime.ext.r.bin.win32.x86_2.12.0%2fR-Inst%2flibraryVersion,Priority,Depends,Imports,LinkingTo,Suggests,Enhances,OS_type,License,Archs,Built.rds', probable reason 'No such file or directory'

 

while trying to find it in the insatll extension option : it shows nothing. even while unchecking the "hide extensions already installed box"