'Tekkit' unresponsive after pressing play

[philyang07]

On the technic launcher, when I press play, the minecraft client shows up as being unresponsive. 

Upon checking the logs, the final lines leading up to the error seem to be 

[B#498]  2019-12-27 17:47:24 [INFO] [STDOUT] Starting up SoundSystem...
[B#498]  2019-12-27 17:47:25 [INFO] [STDOUT] Initializing LWJGL OpenAL
[B#498]  2019-12-27 17:47:25 [INFO] [STDOUT]     (The LWJGL binding of OpenAL.  For more information, see http://www.lwjgl.org)
[B#498]  2019-12-27 17:47:25 [SEVERE] [Minecraft-Client] Realms: Server not available!
[B#498]  2019-12-27 17:47:25 [WARNING] [Buildcraft] Unable to read from remote version authority.
[B#498]  2019-12-27 17:47:25 [WARNING] [Buildcraft] java.io.FileNotFoundException: https://dl.dropboxusercontent.com/u/38558957/Minecraft/Buildcraft/version.txt
[B#498]  2019-12-27 17:47:25 [INFO] [Buildcraft] Version check attempt 3 failed, trying again in 10 seconds
[B#498]  2019-12-27 17:47:25 [INFO] [STDOUT] OpenAL initialized.
[B#498]  2019-12-27 17:47:25 [INFO] [STDOUT] 
[B#498]  2019-12-27 17:47:27 [WARNING] [EE3] Version check stopping after three unsuccessful connection attempts
[B#498]  2019-12-27 17:47:35 [INFO] [Buildcraft] Version check failed

Buildcraft seems to not be able to be installed here?

Note: I'm not using a mojang account; I'm using an old account.

[JaariAtmc]

It will be "unresponsive" until the whole modpack has started. Clicking it before that makes it worse, actually. And that's the buildcraft version check, as in, the update checker. Which doesn't work anymore for the very old TekkitMain, as it is trying to check some dropbox file that doesn't exist anymore. Buildcraft works fine...