IRaMuTeQ - Error R

Hello,
- I installed IRaMuTeQ.
- I installed R 3.1.2, since it is written on the IRaMuTeQ website: "The latest version of iramuteq (0.7 alpha 2) has been tested with R 3.1.2 under Windows Seven."
- When I launch IRaMuTeQ, it indicates that some R libraries are missing: ca, rgl, gee, ape...
- I click "OK" to validate the installation. A process is clearly underway. I click "Check" and find that the libraries are still missing.
- I still try to run an analysis: "Specificities and AFC." A message appears: "Error R None1 None None." This is followed by these messages

!== BUG ==!

• • 
    File "iramuteq.py", line 1057, in OnTextSpec
    
    File "analysetxt.pyo", line 76, in __init__
    
    File "openanalyse.pyo", line 56, in __init__
    
    File "openanalyse.pyo", line 156, in doopen
    
    File "layout.pyo", line 702, in __init__
    IOError
    2
    
    - I try the Reinert method, I receive the same error.
    - I then try to install the libraries directly in R using the syntax: "install.packages('library name')", for example for "ca", which becomes "install.packages('ca'). I receive this message:
    
    Installing package into ‘C:/Users/slaflamme/Documents/R/win-library/3.1’
    (as ‘lib’ is unspecified)
    --- Please select a CRAN mirror for this session ---
    Warning: unable to access the repository index http://cran.utstat.utoronto.ca/bin/windows/contrib/3.1
    
    package ‘ca’ is available as a source package but not as a binary
    
    M
    package ‘ca’ is not available (for R version 3.1.2)
    
    If I change CRAN, the message is the same. The message is the same for the other libraries as well.
    
    - So I look for another version of R, a higher version. I manage to get the method "Specificities and AFC" to work, but not the Reinert method.
    
    - I try on other computers; I encounter the same issues.
    - Two months ago, I didn't encounter these obstacles.
    
    Does anyone, whom I thank in advance, have a solution?
    
    Simon
    
    Configuration: Windows / Chrome 80.0.3987.122