XOOPS_ROOT/modules/system/language/YOUR_LANG/blocks.php
Just replace the string, after the constant. Example
define("_MB_SYSTEM_VACNT","View Account");
define("_CONSTANT", "The constant gets replaced with this string, in the actual mod code.");
...instead of 'View Account' you just want 'Check Yourself'...
define("_MB_SYSTEM_VACNT","Check Yourself");
HTH