I have also occasionally had a related problem where a web page takes unusually long to load (or never started loading at all) from the network (as opposed to the cache, which remains fast) until I disabled Surf Express by turning off the proxy access from Netscape's Preferences options. Reader Ketan Vikal had the same problem. In my case, it may be relevant that I am using a PowerBook 3400 and connecting via its internal modem.
Update: Application menu issues
Surf Express apparently conflicts with URL Manager Pro 2.0, such that the URLMP options in the Application menu does not appear. (Thanks, Cody Charette and Jeff Diamond.)
Cody Charette and Kenneth Anderson have also had problems where Surf Express appears to cause icons in the Application menu to "switch." Kenneth has a web page describing the problem in detail.