Pages won't open specific documents - help

I have updated my Pages app and have several documents that I was working on a couple of days ago.



Today those documents won't open for me to work on.



I am reasonably new to Mac and definitely new to troubleshooting issues - so I really don't know where to start.



Please help



Thank you



Hardware Overview:



Model Name: MacBook Pro

Model Identifier: MacBookPro5,5

Processor Name: Intel Core 2 Duo

Processor Speed: 2.26 GHz

Number of Processors: 1

Total Number of Cores: 2

L2 Cache: 3 MB

Memory: 4 GB

Bus Speed: 1.07 GHz

Boot ROM Version: MBP55.00AC.B03

SMC Version (system): 1.47f2

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