You're using a 32 bit system, therefore 32 bit Java, on a mod pack that is not recommended for 32 bit use.
FTB Lite 2 is the only mod pack that is recommended for use on 32 bit systems, as it's significantly less intense.
With 32 bit java, you're restricted to 1 GB of RAM use for java. That's not enough for this mod pack, it is suggested you use between 2 and 5 GB of RAM for this pack.
Thank you for your help. I didn´t know that because I haven´t read anything about that. I´d be nice if it would be put into the Modpack-Description which Bit-Type is recommended for this Modpack.