I got the following problem after rollup installation: I couldn't publish my workflow anymore...
The answer came from a Dynamics CRM Forum post:
Open web.Config file of CRM website and add the following line to the authorizedTypes Xml node:
<authorizedtype authorized="True" typename="CultureInfo" namespace="System.Globalization" assembly="mscorlib, Version=126.96.36.199, Culture=neutral, PublicKeyToken=b77a5c561934e089">
Do an IISReset
The publication should work!