You are using the Message Audit Log search filter, with an optional filter of Message Size Range. You find that any value used results in an Application error.
This issue has been addressed with the patch 10.8.1-294
Usage of the Message Size Range optional filter is as follows:
|Message size range
|The range must be specified in KB/MB as follows: 5K-1M (to search for messages between 5KB and 1MB). 0K-100K (to search for messages smaller than 100K). In other words, both range values must be specified and both values must have a KB/MB qualifier.
Defined in the Messaging Gateway Administration Guide: