Because the mod isn't in the modpack yet. He made a mistake, and didn't include it in the installer Wait for #10.
As for Search - it would require a total remake of the installer - which isn't going to happen "just like that"
Suggestion @Aslain - Any chance of having a search facility on the install ? Just a simple "Find text" and "Next" button maybe ? Just a thought !!
I ask cos I couldn't find Arty Log either !