Yes the plugin SDK interface was slightly updated to allow for some new functionality and unfortunately this broke the compatibility with the older plugins. Check for old plugins is still missing and because of this old plugins can currently crash LCDInfo.
I was pretty sure that I clearly wrote in the release notes about the change and that old plugins won't work but now that I looked around I couldn't find that info.
You can download the new SDK here: http://www.skippari.net/lcd/alpha/sdk.rar
Your plugin should compile if you just add the configure() function like shown here: http://forum.lcdinfo.com/viewtopic.php?t=448
If it suits your plans you could also give me the source for the LCDInfo part of your plugin so that I could include it with LCDInfo and if some interface changes come, recompile it so that you wouldn't need to. But this is of course up to you.