[R] Error in fromchar(as.character(x)) : character string is not in a standard unambiguous format

[Bob Green]

Hello,

I was hoping for advice regarding resolving the above error.

I have a csv file that contains the following variable:

  $ Order.Made.Date       : Factor w/ 299 levels 
"1-Apr-08","1-Aug-05",..: 278 285 91 286 159 132 108 261 282 147 ...


I want to calculate a variable named F.length, which is today's date 
minus  the values contained in  the variable: April$Order.Made.Date)
I tried altering the date format but continued to receive the same error.

  > F.length <- difftime ("11/04/2008", April$Order.Made.Date)
 > Error in fromchar(as.character(x)) :   character string is not in 
a standard unambiguous format

  > Order.date <- as.Date (April$Order.Made.Date)
  > Error in fromchar(x) :   character string is not in a standard 
unambiguous format
 > Order.date <- 'as.POSIXlt' (April$Order.Made.Date)
Error in fromchar(as.character(x)) :   character string is not in a 
standard unambiguous format

Any suggestions are appreciated,

Bob