Project is not opening (Fatal error! )

I am trying to open a unity project but i am receiving a "Fatel Error" in the middle of importing all assets of project by unity. My project is large in size ( about 4.2 GB ) .and I am using unity iOS trial version 3.5 . The error says that system is out of memory but my computer's RAM is of 5 GB -DDR3 . Is it really a memory problem ? Please guys help me out of this . Thanks in advance :-)

Unity shows the error :

   **Fatal error!**
     
     Could not allocate memory: System out of memory!
     Trying to allocate: 67108868B with 32 alignment. MemoryLabel: Texture
     Allocation happend at: Line:345 in /Applications/buildAgent/work/14194e8ce88cdf47/Runtime/Graphics/Texture2D.cpp
     Memory overview
     
     
     [ ALLOC_TEMP_THREAD ] used: 32752B | peak: 0B | reserved: 262144B 
     
     [ ALLOC_DEFAULT ] used: 69979517B | peak: 170594218B | reserved: 268435456B 
     
     [ ALLOC_GFX ] used: 715365977B | peak: 744726105B | reserved: 826277944B 
     Size           |  Num Used|  Num Free|
          32-63     |         1|         1|
          64-127    |        11|         0|
         128-255    |         1|         0|
         256-511    |         3|         0|
         512-1023   |         1|         0|
        1024-2047   |         4|         0|
        2048-4095   |         3|         0|
        4096-8191   |         4|         0|
        8192-16383  |         2|         0|
       16384-32767  |         4|         0|
       65536-131071 |         1|         0|
     1048576-2097151|         1|         0|
     2097152-4194303|         2|         0|
     4194304-8388607|         0|         2|
     8388608-16777215|         2|         0|
     16777216-33554431|         4|         4|
     33554432-67108863|         1|         0|
     
     Label          |   Allocated|       Count|Largest Alloc
     VertexData     |       69364|          10|       29416|
     Geometry       |         240|           5|          48|
     Texture        |   715296373|          44|    67108868|
     *Total*        |   715365977|          59|         N/A
     
     
     [ ALLOC_TYPETREE ] used: 94440B | peak: 1063080B | reserved: 33554432B 
     
     [ ALLOC_CACHEOBJECTS ] used: 308240B | peak: 2947650B | reserved: 33554432B 
     
     [ ALLOC_PROFILER ] used: 529344B | peak: 529344B | reserved: 16777216B 
     
     UnityEditor.AssetDatabase:LoadAssetAtPath(String, Type)
     tk2dSpriteCollectionBuilder:RebuildOutOfDate(String[]) (at Assets/TK2DROOT/tk2d/Editor/Sprites/tk2dSpriteCollectionBuilder.cs:130)
     tk2dSpriteCollectionTextureWatcher:OnPostprocessAllAssets(String[], String[], String[], String[]) (at Assets/