If I preview a template, then click on the "Save this template" button from the Preview screen, I get the following error:
An error occurred DBD::mysql::st execute failed: Incorrect integer value: '' for column 'templatemapbuildtype' at row 1 at D:\path\to\Movable Type\extlib/Data/ObjectDriver/Driver/DBI.pm line 421.
This is 100% repeatable - the only way to successfully save the template is to click the "Re-Edit this template" button and then Save from the Edit Template screen.
Any and all suggestions appreciated. Thanks.
Reported on Movable Type 4.2

Just to make sure, are you running the final release of 4.2? I reported this exactly against RC4, and it was supposed to have been fixed in RC5.
If you did upgrade through one or more of the pre-release versions, it's possible a file didn't get transferred/overwritten properly. You might try uploading a new copy of lib/MT/Template.pm to see what happens. That was the only one modified in relation to that particular bug so it's an easy check. Otherwise, it might be necessary to re-open the bug with more information from you.
Hi, Su. Yes, I'm running the release version. In fact, I just downloaded and upgraded to 4.21, which I notice was released yesterday. The version info reads Movable Type Pro version 4.21-en with: Community Pack 1.6, Professional Pack 1.2 and lib/MT/Template.pm is timestamped at 8/20/2008 9:34PM, but the problem persists.
This was a fresh upgrade from 3.17 straight to 4.2 - it's never had any 4.x beta or RC code installed. The server is Win2003/IIS6, and the client is WinXP/FF3.0.1
Hi, Su. Yes, I'm running the release version. In fact, I just downloaded and upgraded to 4.21, which I notice was released yesterday. The version info reads Movable Type Pro version 4.21-en with: Community Pack 1.6, Professional Pack 1.2 and lib/MT/Template.pm is timestamped at 8/20/2008 9:34PM, but the problem persists.
This was a fresh upgrade from 3.17 straight to 4.2 - it's never had any 4.x beta or RC code installed. The server is Win2003/IIS6, and the client is WinXP/FF3.0.1
I have been able to reproduce, though I get a slightly different error Saving object failed: DBD::mysql::st execute failed: Out of range value adjusted for column 'templatebuildinterval' at row 1 at C:\Athena\mt\extlib/Data/ObjectDriver/Driver/DBI.pm line 421.
with debugging enabled I also see this
this is only happening on my test box (windows).
Interestingly, I just tried the same sequence of events when creating a new post with Firefox on a brand new blog created from scratch with the Cityscape Austin style from the MT4 Style Library, and I do not get the error.