Not a thought beside uninstalling and after reboot, reinstalling. Sorry! 

I've used the reset data function alot this last week and have not seen that error message.  Did you try closeing out Impulse and restrating it and trying to reset data again? 

It's possible that somehow Impulse has gotten borken.  You might try unintalling Impulse run a clean up program like CCleaner and then reinstall Impulse.

I've gotten that before:

-- [7/3/2009 2:07:45 PM] ----------------------------------------------------
Context:    Updating ApplicationList XML: isv Public
Message:    Server problem or connection issue
Build #:    1268
Exception:    The remote server returned an error: (404) Not Found.
Stack Trace:
   at System.Net.HttpWebRequest.GetResponse()
   at az.a(UpdateParams A_0, Boolean A_1)

just opened it now and got:

-- [8/8/2009 12:19:19 PM] ----------------------------------------------------
Context:    Impulse: WebService: ValidateAccount
Message:    (Result: 0 - Success)
Build #:    1270



-- [8/8/2009 12:19:21 PM] ----------------------------------------------------
Context:    Updating ApplicationList XML: wc
Message:    Updated network xml did not have expected revision (retrieved 88 / expected 89)
Build #:    1270



-- [8/8/2009 12:19:21 PM] ----------------------------------------------------
Context:    Updating ApplicationList XML: myoffice
Message:    Updated network xml did not have expected revision (retrieved 0 / expected 1)
Build #:    1270

I dont' know what it means either 

but nothing bad happened when I clicked reset data 

even though it shows this in the error log:

-- [8/8/2009 12:30:21 PM] ----------------------------------------------------
Context:    Impulse: WebService: ValidateAccount
Message:    (Result: 0 - Success)
Build #:    1270



-- [8/8/2009 12:30:26 PM] ----------------------------------------------------
Context:    Updating ApplicationList XML: isv Public
Message:    Server problem or connection issue
Build #:    1270
Exception:    The remote server returned an error: (404) Not Found.
Stack Trace:
   at System.Net.HttpWebRequest.GetResponse()
   at az.a(UpdateParams A_0, Boolean A_1)



-- [8/8/2009 12:30:30 PM] ----------------------------------------------------
Context:    Updating ApplicationList XML: tdesk
Message:    Updated network xml did not have expected revision (retrieved 640 / expected 679)
Build #:    1270



-- [8/8/2009 12:30:30 PM] ----------------------------------------------------
Context:    Updating ApplicationList XML: avg
Message:    Updated network xml did not have expected revision (retrieved 51 / expected 52)
Build #:    1270



-- [8/8/2009 12:30:33 PM] ----------------------------------------------------
Context:    Updating ApplicationList XML: myoffice
Message:    Updated network xml did not have expected revision (retrieved 0 / expected 1)
Build #:    1270



-- [8/8/2009 12:30:33 PM] ----------------------------------------------------
Context:    Updating ApplicationList XML: futurem
Message:    Updated network xml did not have expected revision (retrieved 0 / expected 7)
Build #:    1270

You have all the luck...in a roundabout way.