This is a question/answer I found that warrants repeating.
In the SalesLogix LAN version under a opportunity grouping I have defined a condition so only records were the EstimatedCloseDate is less than :now is defined.
This same group does not work within SalesLogix web. I get an error – the date entered is not a valid date. Year is not 2 or 4 digits.
Here is a work around:
If you edit the group with the LAN change something save it and then change it back back. The group appears to work.
What Web hot fix are you running the web update 3-5 has a defect in the group builder there is a web update 06 in the works to repair the dates in the group builder.
Swap out all your GroupBuilder.DLL’s with the following version (18.104.22.16877) – this seems stable at the moment.