DateValue Function Error

I imported data from MS Project 2013 into an Excel worksheet (copy/paste). The data included some date values. In a second spreadsheet I used the HLOOKUP() function to bring in a set of column information in order to do standard reporting. When I tried to do some conditional formatting based on date column comparison I found it did not work. I realized the dates were text by using the ISTEXT() function. I tried using the DateValue() function in order to convert and do the comparisons, but keep getting a #Value! error. The columns are general format. Any suggestions?

I have attached a sample file. The file contains a worksheet with the data and a reporting worksheet. The reporting worksheet contains a text box explaining the desired conditional formatting. I did try the the various solutions with no success. The intent is to have no user intervention other than pasting in the data into the worksheet named DataSheet.

Thank you all for the replies/suggestions. I was able to create a "flag" column using Tony's suggestion and using that to perform the conditional formatting as well as view filtering, etc.