File Time Stamps are incorrect
Windows Explorer can display file timestamps incorrectly due to Daylight Saving Time differences.
If you create a file on February 9 (outside DST) at 3:45 pm then roll your clock forward to June 2 (inside of DST with adjustment for DST) you expect the time to still be 3:45 pm for that file? Windows Explorer will display it as 4:45 pm.
Using the above scenario you check out a file from StarTeam (that was checked in or added on February 9th at 3:45 pm) and force the last modified time (i.e. set the option "Use last modification time for checked-out files") and check out the file on June 2 (during Daylight Saving Time) Windows Explorer displays the timestamp as 4:45 pm. StarTeam correctly displays the last modified time as 3:45 pm.
This is Windows behavior.