When creating component, in manifest file, xml, name of the component must be name of file which are you using.

This example will work:

<?xml version="1.0" encoding="utf-8"?>
<install version="1.5.0" type="component">
  <name>Component</name>
  <author>Stanko MiloL?ev</author>
  <version>1.0.0</version>
  <description>Search for taxpayers from database</description>
  <files>
    <filename component="com_regdavzav">Component.php</filename>
  </files>
  <install>
  </install>
  <uninstall>
  </uninstall>
  <administration>
    <menu>Registar davÄTnih zavezancev</menu>
  </administration>
</install>

This example will not work:

<?xml version="1.0" encoding="utf-8"?>
<install version="1.5.0" type="component">
  <name>Component</name>
  <author>Stanko MiloL?ev</author>
  <version>1.0.0</version>
  <description>Search for taxpayers from database</description>
  <files>
    <filename component="com_regdavzav">com_component.php</filename>
  </files>
  <install>
  </install>
  <uninstall>
  </uninstall>
  <administration>
   <menu>Registar davÄTnih zavezancev</menu>
  </administration>
</install>

Because  <filename component="com_regdavzav">com_component.php</filename>, com_component.php is different from Component as it is defined in <name>Component</name>