title: glm probit "cannot find valid starting values" error message
body: <p>I am trying to use R for the first time to do some probit analaysis.</p>
  
  <p>I get the following error:</p>
  
  <p>Error in if (!(validmu(mu) &amp;&amp; valideta(eta))) stop("cannot find valid starting values: please specify some",  : 
    missing value where TRUE/FALSE needed</p>
  
  <p>This is the command I am using:</p>
  
  <pre><code> m1=glm(Good~Stg.Days+Dev.Deployments+Check.Ins+NoOfDevelopers,family=poisson(link = "probit"),data=deploy[1:4,])
  </code></pre>
  
  <p>My data deploy[1:4,] are as loaded in from a CSV file follows:</p>
  
  <pre><code>Good,Application Type,Project,Start Date,End Date,Stg Days,Dev Deployments,Check Ins,NoOfDevelopers
  1,DocumentPlatform,ZCP,11/08/2010,11/11/2010,0.6,0,12,4
  1,DocumentPlatform,ZCP,11/11/2010,09/12/2010,0.4,0,4,1
  0,DocumentPlatform,ZCP,09/12/2010,07/03/2011,10,0,7,3
  1,FactsheetPlatform,Process.ARCH,28/06/2010,09/03/2011,7.1,0,18,2
  </code></pre>
  
  <p>deploy is in reality a much bigger vector than 1:4 I am just using a subset of the data to help determine the problem.</p>
  
  <p>Any ideas what is wrong?</p>