Have you tried deleting the CPD file?
I just tried it and had the same result. Crash.
I was able to apply a condition tag on a book in the TOC without crashing.
Problem Event Name: BEX
Application Name: RoboHTML.exe
Application Version: 10.0.1.292
Application Timestamp: 51493787
Fault Module Name: StackHash_0a9e
Fault Module Version: 0.0.0.0
Fault Module Timestamp: 00000000
Exception Offset: b43fb03f
Exception Code: c0000005
Exception Data: 00000008
OS Version: 6.1.7601.2.1.0.256.48
Locale ID: 1033
Additional Information 1: 0a9e
Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
Additional Information 3: 0a9e
Additional Information 4: 0a9e372d3b4ad19135b953a78882e789
OMG, it seems to have resolved itself! I copied some conditionalized text to another location in the document as a workaround to applying the condition, and now suddenly the Apply Conditional Tag menu works and doesn’t crash RoboHelp! All I can say is YAY!!