I created a simple module and now I want to add a block.
I copied/modified the necessary pieces from a system block to create
1) xoops_version.php
$modversion['blocks'][1]['file'] =
$modversion['blocks'][1]['name'] =
$modversion['blocks'][1]['description'] =
$modversion['blocks'][1]['show_func'] =
$modversion['blocks'][1]['template'] =
2) templates/blocks/mymod_block_stuff.html
contains the html to display block content
3) blocks/mymod_blocks.php
contains the show_func function

The module update succeeded, but after configuring Groups and Blocks for it to be visible as a R-Block, nothing displayed. Echo tracing revealed that the show_func function was being called but <{$block.content}> was empty in my theme.html.

I found the original problem - I spelled the template file wrong in xoops_version.php. But after correcting this misspelling, now the module will not update. The page rendering of the module update process stops with the line
<div class='content'><br />

Even with just a hard coded unordered list in the block template file, the update still fails. Neither PHP Debug nor Smarty Template Debug show any errors.

Where should I look for the problem?
[Xoops 2.0.7.3]

Thanks.