Hi @KumarS,
Something weird is happening with your install by the look of it. First, restart a "plain-vanilla" session of RStudio and do not load any startup code. Then, can you re-run the "forecast" install and post the output here? I assume you are installing package pre-compiled binaries (from CRAN) and not compiling the source code versions? Binaries are likely to give you less problems (and be much quicker). The output from running the following code will also be useful for diagnosis:
sessionInfo()
packageDescription("forecast")
packageDescription("timeDate") # Since this was referred to in the error message
HTH