Weekend clock does not apply in this case because Vilma sold prior to the cut-off at 11:59pm on Saturday. Years and cuts thus needed to be declared within 24 hours of the winning bid.
Your IDP roster was full. Since the necessary cuts were not made in time. Vilma goes bck into the FA pool and Bounty Hunters may not bid on Vilma for 30 days.
From section 9B. In-Season Free Agent Acquisitions:
Bidding for Free Agents will take place each week from 12:00am Tuesday until 11:59pm Saturday. Exceptions to this schedule will occur during weeks where there are Thursday games. During these weeks, Bidding will begin at 12:00am Tuesday, and end at 11:59pm Saturday however, players involved in the Thursday game(s) cannot be bid upon from gametime Thursday until the following Tuesday at 11:59pm.
If a player's 24 hour challenge period hasn't expired prior to 11:59pm on Saturday, bidding on that player will suspend until the following Tuesday at 12:00am when the 24 hour clock will resume.
If a bid is made on any player between 12:00am Sunday and 11:59pm Monday the bid will be treated as if it were made on Tuesday at 12:00am and the 24 hour challenge period will not begin until that time. Also note, that for players involved in Thursday or Saturday games, the clock will suspend the evening prior to their game(s) at 11:59pm and won't resume until the following Tuesday at 12:00am.
Rules link:
http://sacd.predsff.com/OfficialSACDRules.html