Error or Warning Message

Error 58186 "Full Text Search execution failed.  External module has reported an error." 

Explanation

Generally this is because the Microsoft Index catalog has become corrupt.  This can happen for various reasons, as Microsoft explains here http://support.microsoft.com/kb/209304

"Catalog corruption is most commonly caused by the following:

• When you run a backup or virus scan against the Catalog.wci directory when Index Server is started. Because Index Server keeps many of the files in that directory open and mapped into memory, a backup can corrupt them as it may lock them in order to back them up. To work around this, either stop the Index Server (CISVC) or simply remove that directory from the list of directories you back up.
• Anytime you restart a computer without shutting it down from the Start menu, you run the risk of corrupting files, and the Index Server catalog files are no exception.
• If you edit the registry and set the FilterRetries key in the following location to a value below 4 (default is 4):
  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ContentIndex
• Multiple catalogs indexing the same directories."

Bentley support can provide a tool to test a search of the catalog directly to verify if this is the case

How to Avoid

Also from Microsoft (http://support.microsoft.com/kb/209304)

1. Stop Microsoft Indexing service

2. Delete catalog.wci (default directory C:\ProgramData\Bentley\index-storage)

3. Start Microsoft Indexing service

The calalog will be recreated using the data already extracted out of the ProjectWise files. 

See Also

http://support.microsoft.com/kb/209304